When enabled (the default), share links to YouTube videos point to the
active source's web watch page instead of youtube.com. Invidious serves
its frontend at the API URL; Piped uses its configured frontend URL.
Videos the active source can't serve (PeerTube, extracted sources) and
sources without a web frontend keep their original links.
The toggle lives in Settings > Layout & Navigation > Sharing on iOS and
macOS, and is shown only when an enabled source has a web watch page.
An account with no user-set label was named username@host everywhere it
appears — the switcher menu, the settings rows, the playlist selector —
which overflows a menu row the moment the host has a subdomain. The
default name and the switcher's disambiguation suffixes now use the
instance's title when one is set, falling back to the host as before.
MAC6: a snapshot mutation carries its video count back to the list cache.
MAC8: playlist rows and cards are Buttons with the context menu attached,
so macOS accessibility can reach Edit and Delete.
MAC10: a published date stamped with the request's own time is dropped at
both API sentinels, and formattedPublishedDate refuses zero-interval output.
MAC11: a failed history hydration shows Details unavailable with a Try
Again action instead of keeping the raw video ID forever; an empty 200
body is a legible failure.
Ten review findings in the remote-playlist work, all of them the same
shape: something acted on what it remembered instead of what the server
says now.
- A confirmed-gone playlist is forgotten whole — snapshot, list entry,
and both ordering fences — so a refresh that started before the delete
can no longer republish it, and a list refetch that fails offline no
longer leaves it on screen.
- `.accountsDidChange` discards account-scoped content when the account
it belonged to is no longer the effective one, as the status
notification already did.
- A tab that stops being offered no longer stays selected: the browse
view moves to the first available one, which reloads by itself.
- A Handoff account id is accepted only when that account is on the
instance the playlist lives on.
- Composite writes moved up into `AccountService`, over a transport whose
every method is exactly one request: create-with-privacy, rename, and
set-description. The credential is rechecked between each pair, so a
sign-out between the two halves of a create or an edit can no longer
send the second half under the previous user's secret.
- Editing a playlist no longer forces it private. Invidious serialises
visibility as `isListed` — `privacy.public?`, so unlisted and private
are indistinguishable — which the snapshot now carries; the picker
starts there, and sends nothing at all unless it was moved. Invidious
keeps the stored visibility when the PATCH omits it (measured), so an
untouched picker leaves it exactly as it was.
- Tapping Edit on a server-side playlist awaits an authenticated refetch
first and populates the form from it; a failed refetch shows an error
and no sheet.
- Playlist rows are keyed by row rather than by video id, which two rows
of the same video share.
- The add-to-playlist sheet offers only accounts whose instance is
enabled and that hold a credential, alongside the write capability.
Remote playlist entries carried the display row number as their server
position, so a row the app could not parse shifted every removal after it
by one, and rows were paired back to entries by video id, which cannot
tell two copies of the same video apart.
- Piped entry positions are now the raw stream index; entries carry a
separate displayRow for the row they are drawn as, filled in by both
snapshot builders and used by the detail view's row map
- an emptied description clears a server-side playlist instead of being
read as "leave it alone"
- a delete that reported failure forgets a playlist the refetch 404s on,
and drops it from the account's cached list
- the browse view discards account-scoped content when a status change
moves which account the instance resolves to
- every mutation re-reads the credential immediately before it is sent,
which matters most after Piped's verify-before-remove fetch
- Handoff carries the owning account id, so a Piped playlist keeps its
ownership on the receiving device
Reading a server-side playlist was all the app could do: the write half of
both APIs was missing, and the only thing that knew which credential to use
was the subscription layer. So playlists arrive here as an account concern —
hand AccountService an account and it finds the instance, reads the secret,
refuses what the backend cannot do, and records what the answer implies
about the login.
Capabilities decide, never the instance type: a privacy setting sent to a
backend that has none is dropped rather than refused, because the playlist
is still perfectly creatable there. Every call captures the credential it
used and re-reads it before recording an outcome, so a late 401 cannot
reject the login the user just fixed, nor a late success clear a rejection
it never earned.
Removal is where the backends stop being alike. Invidious names the row
itself with an indexId that survives refetches, so it removes directly.
Piped removes by position, and a position is only true of the fetch that
minted it — so the playlist is refetched and the position checked to still
hold the same video before anything is deleted. That narrows the window; it
cannot close it, and only the refetch afterwards shows what really happened.
The cache exists so that refetch cannot be forgotten. Every mutation goes
through it and republishes what it touched — on failure as much as on
success, because a write that reported failure may still have landed — and
nothing is ever edited optimistically. It is in memory alone: the data
belongs to a login rather than to this device, and a stored Piped entry id
would be aimed at whatever occupies that slot next launch. A per-account
generation fences results that come back after the account was cleared,
since clearing has never cancelled the request that was filling it.
Along the way, clients minted per instance sent no User-Agent at all —
instances that whitelist the Yattee prefix answered them with a 401 the
shared client never earned. The factory now bakes the app's User-Agent in
at construction, where no request can outrun it.
Playlist fetches threw away the only handle a row could be removed by:
Invidious hands out an index/indexId pair per entry and both were dropped
on conversion, so nothing downstream could say which row it meant.
Both authenticated fetches now also return a snapshot — the playlist plus
its addressable entries. Invidious entries carry the server's indexId and
survive refetches; Piped has no such token, so its entries are addressed
by position and are only valid inside the snapshot that minted them. The
entry id carries the playlist id in both cases, so position 3 of one
playlist can never be mistaken for position 3 of another.
A row needs both an indexId and an index to be a target: rows missing
either are still displayed but never appear in entries, so no removal can
be aimed at a row the server refuses to name. Page-overlap dedupe stays
keyed on index and never on videoId — the same video may sit in a
playlist twice, and each copy is its own removable row.
Two devices editing an account in the same instant — or migrating one,
since every migrated account is stamped at the epoch — each kept its own
label and considered the matter closed. Equal timestamps are now broken
by the label, on the incoming side and in the conflict resolver alike,
the same rule the context already uses.
Cached feeds were thrown away on every ordinary launch: recomputing
statuses posts a notification, and the observer ran before the value it
compares against had been seeded. The seed now happens first.
Cache ownership is checked once at launch and compared against a
recorded owner afterwards. An unresolved identity at launch means the
owner cannot be established at all — a switch to an unseen Apple account
while offline looks exactly like that — so the caches are discarded;
mid-session it is a transient, and with iCloud Drive off it happens on
every activation, so it no longer clears anything.
Whether a Keychain item syncs is fixed when it is written, so a login
stored while sync was off stayed on this device while its account record
travelled, leaving every other device with an account whose credential
never arrives. Turning sync on rewrites them.
Reseeding a deleted zone marks the account records dirty even while the
category is off, so re-enabling it restores them instead of finding an
empty outbox.
An additional login could be created but never selected: the legacy
picker lists one entry per instance and always resolved to whichever
account signed in first. Account rows gain a "Use This Account" action,
and the subscriptions view reloads on the data context rather than on
the legacy setting — two logins on the same instance map onto the same
legacy value, so switching between them changed nothing on screen while
writes went to the other account.
Two devices migrating different legacy selections produced contexts with
identical epoch timestamps, and each refused the other's: a permanent,
silent divergence that both sides considered settled. Equal timestamps
are now broken by the selected account's ID, on the incoming side and in
the conflict resolver alike — a record that wins the upload must not be
refused on arrival.
Credential cleanup falls back to both managers whenever the backend
cannot be resolved, not only when the account is unknown here: an
instance deletion can arrive before the tombstone, and the credential
was then left in the Keychain.
Yattee 2 could hold at most one login per instance: a Keychain item keyed by
the instance UUID and a Bool on the instance. This adds the account layer
the rest of the revamp builds on.
DataContext (.local or .account) replaces SubscriptionAccount as the thing
that selects a data set. The legacy value maps onto it as an identity
mapping, because migrated accounts deliberately reuse their instance UUID.
Contexts carry an app-managed changedAt, and a migrated one is stamped at
the epoch so any explicit choice on any device outranks it whatever order
they arrive in.
AccountCapabilities makes what a backend supports a single switch in
InstanceType.accountCapabilities, verified against each API surface -
Invidious has history and playlist privacy, Piped has neither. Call sites
ask for capabilities instead of switching on instance type, which is the
seam the planned per-user Yattee Server accounts land on.
AccountsManager owns accounts and the selected context, stored per identity
scope so a switch of Apple Account cannot show or upload the previous one's
list. Legacy single-logins become accounts through a repeatable
reconciliation rather than a one-shot at launch, because instances arrive
over iCloud whenever they arrive; a permanent marker set is what makes
re-running safe, since usesAccountLogin stays true on the instance forever
and would otherwise recreate a deliberately deleted account. A dirty-flag
outbox records what still needs uploading so an offline change survives a
crash. The legacy subscriptionAccount selection is migrated one way,
reading local defaults first and then the raw KVS value - the previous
release published that key to iCloud but never read it back, so on a fresh
install it exists only there.
DataContextValidator replaces SubscriptionAccountValidator, which corrected
any selection it could not immediately verify. That was safe when a context
was just "an instance I am logged into", but with credentials arriving
asynchronously it would discard the user's choice during a slow Keychain
sync. Validity is now tri-state: anything that might still resolve keeps
the selection and falls back to local for reads only, with server mutations
disabled rather than silently retargeted at local data; only an actual
deletion corrects the stored context.
EditSourceView's single log in/out pair becomes a list of accounts with
per-row status, sign-in-again and sign-out-and-remove, plus the explicit
"use saved login from this device" action - the one-tap adoption that
replaced automatic adoption after the Keychain provenance measurement. On
tvOS a credential-less account offers a local sign-in instead, since Apple
never syncs app Keychain items there and the state will not resolve on its
own.
InstanceLoginView now returns the identifier alongside the credential so
the caller can file it in the Keychain beside the secret, keeping login
identifiers out of synced metadata.
Yattee 2 keys credentials by instance UUID with no notion of which Apple
account they belong to, and reads them back with SynchronizableAny. Apple
documents that Keychain data may stay on device when a user signs out and
chooses to keep it, so whoever signs in next would be served the previous
user's credential - guaranteed for migrated accounts, since local instances
survive the switch and the migrated account UUID is deterministically the
instance UUID.
Credentials are now keyed "<identityScope>|<accountID>", where the scope is
the CloudKit user record (identical across a user's devices, so iCloud
Keychain sync still works). Usernames get the same scope and live beside the
credential, keeping login identifiers out of synced metadata.
The legacy unscoped item is never adopted automatically. A strict
kSecAttrSynchronizable == true query was the candidate discriminator for
"this secret belongs to the current Apple account", but measured on iPadOS
27.0 a retained item keeps the attribute and still matches that query with
no Apple account signed in at all - the flag records what was once requested,
not live iCloud Keychain membership. Reads therefore never fall back to the
legacy key; adoption is an explicit user action that copies the item,
verifies the scoped read-back, then records a marker bound to the identity
and a salted fingerprint of the secret. The legacy item is retained, because
deleting a synchronizable item propagates and would log out devices still on
the previous release mid-rollout. Deleting it later needs all three of: a
marker on this device, matching identity, and the item still holding the
adopted secret.
The instance-keyed path is untouched, so no shipping call site changes
behavior. BasicAuthCredentialsManager stays instance-keyed - proxy auth
belongs to the instance, not to a user account.
While the scope is unresolved (first launch under a new Apple account,
CloudKit unreachable) reads report "can't tell yet" via isScopeResolved
rather than "signed out", and writes are refused rather than guessing a
scope. Login state is cached per scope so one identity's cache can never
answer for another.
Also adds the debug-only harness the measurement was taken with, under
Advanced > Developer > Experiments.
MPVTrack.detailText built its sample-rate label with integer division
(`sampleRate / 1000`), which truncates the fractional kHz. The
second-most-common audio rate — 44100 Hz (CD quality, music videos) —
showed as "44 kHz", a label that denotes 44000 Hz (a different rate),
instead of the conventional "44.1 kHz" used by VLC, mpv and every DAW.
The same defect hit 88200 -> "88 kHz", 176400 -> "176 kHz" and
22050 -> "22 kHz". Whole-kHz rates (48000, 96000, ...) were already
correct and stay unchanged. The label is live in the quality selector's
advanced details, where EmbeddedTrackRowView renders track.detailText.
- Factor the formatting into MPVTrack.formatSampleRate(_:), a pure
static helper: divide as Double, drop the decimal for whole kHz,
otherwise keep 1-2 meaningful digits with the trailing zero stripped
(44.1, 88.2, 22.05).
- detailText now appends Self.formatSampleRate(sampleRate); its structure
(codec / channelCount parts, separator, nil-when-empty) is unchanged.
- Add YatteeTests/MPVTrackFormatTests covering whole-kHz rates, the
44.1 kHz family (the bug), half-decimal rates and the detailText
integration.
The previous fix rebuilt the quality chain when converting persisted
models back to videos, but many consumers discarded it again by
rendering bestThumbnail (usually a maxresdefault.jpg that 404s for
older videos) as a single URL with no fallback.
Extract the retry logic from VideoThumbnailView into FallbackLazyImage
and use it at every in-app site that can iterate: player thumbnails
(mini bar, expanded sheet loaders, autoplay previews, tvOS audio-mode
artwork - previously a silent black screen), video info card and tvOS
header, and the tvOS playlist cover.
Sites that fetch or send exactly one URL are rewritten to the
always-available hqdefault variant via Thumbnail.reliableURL (exposed
as Video.reliableThumbnailURL): Now Playing artwork, Top Shelf
snapshots, remote control state, the frozen transition thumbnail,
blurred info background, navigation covers, and playlist covers
derived from a video's first thumbnail in Invidious/Yattee Server
responses.
Also invert RecentPlaylist's upgrade helper, which rewrote covers *to*
maxresdefault, walk the quality chain when caching download thumbnails
for offline artwork instead of giving up after one 404, and expand the
remaining single-thumbnail Piped conversions into full chains.
Persistence models (local playlists, watch history, bookmarks,
downloads) store only the best advertised thumbnail URL - usually
maxresdefault.jpg, which doesn't exist for many older videos and 404s.
Live API results survive this because views fall back through the full
quality chain, but toVideo() rebuilt videos with that single dead URL,
leaving placeholder covers.
Reconstruct the quality fallback chain from the stored YouTube-style
URL at read time (Thumbnail.fallbackChain), and rewrite playlist list
covers to the always-available hqdefault variant
(Thumbnail.reliableURL), since those views render a single URL without
fallback. Also expand the fabricated maxres URL in PipedAPI into a
full chain.
Adds a "Load subtitle from file…" row to the Subtitles section on iOS
(document picker) and macOS (open panel), available when playing files
from local folder, SMB, or WebDAV sources. The picked file is copied
into the per-video temp subtitle directory, registered as a selectable
Caption (displayed by filename), and activated through the existing
loadCaption flow. The Subtitles tab and captions control button now
also appear for media-source files without any subtitles.
Streams built for local folder files carry no resolution/codec/fps
metadata (unknowable before demux), so the quality selector labeled
them "Unknown". Use the video track mpv reports (demux-w/h/fps, codec)
to fill those fields into a display-only copy of the stream — the
Video row and summary now show e.g. "720p · 30fps" with a codec badge.
Selection and tap handling keep using the original stream.
Files with multiple embedded tracks (e.g. MKV from media sources or
downloads) previously exposed none of them: mpv's track-list was never
read, aid was never set, and sid was only ever no/auto. The quality
selector showed no Audio or Subtitles tab for such files.
MPVClient now observes track-list/aid/sid and delivers a coalesced,
leniently decoded [MPVTrack] snapshot; selection state is derived from
the reported "selected" flags. Embedded tracks are switched live via
aid/sid (no reload), surfaced in the existing Audio/Subtitles sections
alongside external captions on iOS, tvOS and macOS. External sub-add/
audio-add tracks are filtered out to avoid double-listing. User picks
are sticky across same-video reloads (quality switch, audio mode,
retries) and preferred audio/subtitle languages auto-select a matching
embedded track once per load, with external captions taking precedence.
After reinstalling the app and importing sources from iCloud, remote
server instances with Keychain-only credentials showed no indication
that login is needed, unlike WebDAV/SMB sources.
- Show the orange key icon for Yattee Server instances without stored
basic auth credentials (auth is always required for this type)
- Persist usesBasicAuth/usesAccountLogin flags on Instance (synced via
iCloud) so missing Invidious/Piped/PeerTube credentials are detectable
too; maintained on credential save/delete, login/logout, and legacy
migration
- Centralize the check in AppEnvironment.needsCredentials(for:) used by
SourcesListView, MediaSourcesView, and SourceRow
- Backfill the flags at launch from credentials currently in the
Keychain so existing setups publish them without a re-login
Downloads bypass stream selection and reach play() as ready-made local
file streams, so audio mode never affected them. Apply the mode at that
choke point instead: swap a local video stream for the separately
downloaded audio track, or play a muxed file with the video track
disabled (vid set per-load in MPVClient, never toggled live). The
transform is bidirectional so stored audio-only queue/history entries
restore full video when the mode is off, and setAudioMode now reloads
downloaded content at the current position in both directions.
Persistent per-platform mode that plays only the audio track to save
bandwidth and speed up loads. When enabled, stream selection picks the
best audio-only stream (preferred language, codec, bitrate) and never
fetches the video URL; toggling mid-video reloads at the current
position using the quality-switch path (live vid=no toggling is avoided
due to A/V desync).
- Toggle row in the player quality/settings sheet on iOS, macOS and
tvOS, next to lock controls
- New audioMode control button type (red when active) for player
controls and mini player layouts
- Picking a video quality explicitly turns the mode off; audio track
picks keep it on and now work while audio-only is playing
- Stream URL refresh preserves audio-only playback instead of
resurrecting video
- Queue preloads and history entries resolved before a toggle are
discarded so selection re-runs with the current mode
- tvOS player shows the video thumbnail instead of a black screen
during audio-only playback
- PiP button hidden for audio-only streams
Playback menu seek items now follow the durations from the active player
controls preset instead of hardcoded 10s/30s labels. AppEnvironment caches
the active preset's center settings (refreshed on preset change
notifications) so menu commands can read them synchronously.
Add secondary seek durations (default 30s) to CenterSectionSettings,
configurable on macOS in Seek Durations settings, used by Shift+arrows in
the player and Cmd+Shift+arrows in the Playback menu.
Also let Cmd-based key equivalents pass through the player keyboard
monitor so menu shortcuts (e.g. Cmd+Option+arrow previous/next video)
work while the player window has focus, and unify macOS built-in preset
primary seek at 10s to match iOS/tvOS (built-in presets version 8).
Rename the macOS "Control Bar Buttons" settings entry to "Control Bar"
and add an Auto/Light/Dark glass background picker on that page. The
choice is stored per-preset as GlobalLayoutSettings.controlBarTheme and
forces the bar's glass color scheme via glassBackground(colorScheme:).
Render the macOS control bar button row and top bar from the active
preset's sections via a new MacOSControlsSectionRenderer, replacing the
hardcoded QuickTime-style rows in MacOSControlBar. Add a keepOnTop
button type and macOS-specific button availability lists, and adapt the
player controls settings editors (preset editor, section editor, button
configuration) for macOS.
Also apply the preset font style to the control bar time labels, and
update the built-in macOS Default preset order (queue before transport,
fullscreen at the end), bumping builtInPresetsVersion to 7.
Surface audio-delay (±10/±100 ms) and video-sync-mode controls behind an
"A/V Sync" navigation row in Advanced settings rather than inline, keeping the
Advanced page uncluttered. Audio delay applies live to the running MPV
instance; sync mode takes effect on next playback.
YouTube's CDN advertises maxres/sddefault thumbnails for every video but
only generates them for sufficiently high-res uploads, so older/low-res
videos return 404 for those qualities. The view picked the best quality
and showed a blank placeholder on failure with no fallback.
VideoThumbnailView now accepts an ordered fallback chain and advances to
the next candidate via NukeUI's onCompletion when a load fails, so a valid
thumbnail is always shown. DeArrowVideoThumbnail feeds it DeArrow branding
first, then the video's own thumbnails best-quality-first.
Render subscriber count, Subscribe button, and (for subscribed
channels) description in the tvOS loading state instead of just
avatar + name + spinner. Seed the in-memory author cache when
navigating to a channel from a video so the first-time channel
view has a name and avatar to display immediately.
After iOS reinstall/restore the app container UUID rotates, which left both
the persisted source.url and the security-scoped bookmark pointing at a
no-longer-current path. Files derived a stale absolute path that got appended
onto the resolved bookmark, producing doubled URLs that MPV could not load.
- Resolve the base URL by picking whichever of the bookmark or source.url
actually exists on disk.
- Compute MediaFile relative paths against the resolved root so they survive
later container changes.
- Hold the security-scoped resource access for the source's lifetime via a
shared resolver, so MPV can open files long after the directory enumeration
that resolved the bookmark has returned.
- Normalize legacy absolute paths embedded in old recents/history video IDs
so they re-resolve under the current container.
Piped's session token reuses the Authorization header, so a fronting basic
auth proxy can't coexist with logged-in Piped use — the two would clobber
each other's credentials on every authenticated request.
Add a supportsHTTPBasicAuthProxy capability on Instance/InstanceType (false
for Piped, true for everything else) and route it through:
- AddRemoteServerView refuses Piped if detection only succeeded behind basic
auth, surfacing a localized "not supported" error instead of a silently
broken instance, and hides the optional credentials section for Piped.
- EditSourceView hides the basic auth fields for Piped instances and clears
any legacy stored credentials on save, in case a Piped source was added
with credentials before this change.
The Sources -> Edit Source -> Proxy toggle now renders for Yattee
Server entries (supportsVideoProxying gains .yatteeServer). When the
toggle is on, playback fetches go through
videoWithProxyStreamsAndCaptionsAndStoryboards with mode .relay, so
the server returns signed /proxy/relay URLs (byte-relay, supports
HTTP Range, no on-disk caching). Downloads keep going through mode
.download so the server-side /proxy/fast/ flow continues to cache
files for repeat use.
InvidiousAPI.proxyStreamsIfNeeded early-returns for .yatteeServer
since proxying is now done at fetch time via ?proxy=true rather than
client-side host rewriting.
Remove the gear toolbar button that opened Settings as a sheet in the
NavigationSplitView sidebar column, and drop the macOS guard hiding
.settings from SidebarMainItem so it can be added to the sidebar and
rendered in the detail column like other items. The dedicated Settings
window (Cmd+,) is unchanged.
Exposes ContinueWatchingView as an opt-in compact tab bar item,
hidden by default. Uses a short "Continue" label since the full
"Continue Watching" string does not fit as a tab bar title.
Playable files in the media source browser now honor tvOSVideoTapAction
on tvOS and thumbnailTapAction/textAreaTapAction on iOS/macOS, matching
other video lists. When openInfo navigates to VideoInfoView, playback
routes through QueueManager.playFromMediaBrowser so stream and caption
resolution keep working for Samba/WebDAV files.
yattee-server returns direct YouTube CDN URLs in the storyboard `url`
and `templateUrl` fields instead of an Invidious-style VTT proxy path.
Two resulting issues:
- `Storyboard.directSheetURL` was replacing the whole `M$M` token with
just the index, producing `.../0.jpg` (404) instead of `.../M0.jpg`.
Replace `M$M` with `M\(index)` to preserve the literal `M` prefix;
matching the full token also avoids clobbering `$M` sequences that
may appear in `sigh=rs$...` query params.
- The download code fetched `proxyUrl` as if it were a WebVTT file;
with yattee-server that downloads a JPEG that fails UTF-8 parsing.
Skip the VTT round-trip when `proxyUrl` obviously points at an image.
Also align the on-disk filename with the local-playback template
(`sb_M$M.jpg` → `sb_M{N}.jpg`) so offline seek-bar previews resolve,
and add [Storyboard] debug logs at each decision point so future
failures can be diagnosed without guessing.
After disabling home shortcuts on tvOS, Open URL and Remote Control had
no entry point. Add them as configurable sidebar main items. Remote
Control defaults to visible on tvOS; Open URL defaults to hidden on all
platforms.
Preserve user:pass credentials in instance URLs so Invidious instances
behind nginx reverse proxies with HTTP basic auth work correctly (#926).
Add displayURL property to mask credentials in the UI.
Adds a "Proxy videos" toggle in instance settings that routes video
streams through the instance instead of connecting directly to YouTube
CDN. Includes auto-detection of 403 blocks and live re-application of
proxy settings without requiring app restart or video reload.
The filter strip was passing the Invidious instance URL as serverURL to
AvatarURLBuilder, which built a Yattee Server-style /avatar/ path that
doesn't exist on Invidious. Now passes the actual Yattee Server URL
(matching SubscriptionsView pattern) and enriches channels from
CachedChannelData as a fallback when the API doesn't return thumbnails.
Back the in-memory authorCache with a JSON file in ~/Library/Caches/AuthorCache/.
Disk is lazy-loaded on first lookup and saved asynchronously on each cache update.
Capped at 500 entries to prevent unbounded growth.
- Cache author data from video detail API responses (PlayerService, VideoInfoView)
- Replace ChannelView's private CachedChannelHeader with shared CachedChannelData
- Enrich author with cached avatar/subscriber count in VideoChannelRow, TVDetailsPanel, VideoInfoView
