Resume and seek when reopening currently-loaded video

When the same video was already loaded (typically paused), opening it
again via the URL scheme, a deep link, or a remote-control loadVideo
command did nothing — the player just stayed paused. Now the same-video
early-return path resumes playback if paused and seeks to the supplied
startTime, so timestamps from URLs and remotes are honoured even when
the video is already loaded.

URLRouter gains a parseTimestamp helper that reads t/time/start query
params in plain-seconds and YouTube-style (1h2m3s) forms, and the deep
link handler now forwards that timestamp through to openVideo.

Yattee/Services/Player/PlayerService.swift

@@ -916,12 +916,23 @@ final class PlayerService {
         let mpvPiPActive = false
         #endif
 
-        // If this video is already playing, just expand the player (unless PiP is active)
+        // If this video is already loaded, optionally seek/resume instead of reloading.
         if isCurrentlyPlaying(video: video) {
-            LoggingService.shared.logPlayer("Video already playing, just expanding")
+            LoggingService.shared.logPlayer("Video already loaded, applying seek/resume instead of reload (startTime=\(startTime ?? -1), state=\(state.playbackState))")
             if !mpvPiPActive {
                 navigationCoordinator?.expandPlayer()
             }
+            let wasPaused = state.playbackState == .paused
+            if let startTime {
+                Task { @MainActor in
+                    await seek(to: startTime)
+                    if wasPaused || state.playbackState == .paused {
+                        resume()
+                    }
+                }
+            } else if wasPaused {
+                resume()
+            }
             return
         }
 
@@ -958,11 +969,14 @@ final class PlayerService {
         let mpvPiPActive = false
         #endif
 
-        // If this video is already playing, just expand the player (unless PiP is active)
+        // If this video is already loaded, optionally resume instead of reloading.
         if isCurrentlyPlaying(video: video) {
             if !mpvPiPActive {
                 navigationCoordinator?.expandPlayer()
             }
+            if state.playbackState == .paused {
+                resume()
+            }
             return
         }