feat: contraband list with flagging and optional removal

Staff list contraband items on a new dashboard page (item search, reason, flag or flag and remove;
contraband_manage to edit, reports_view to see). World servers check every inventory when a
character loads and every item a player receives: each find is an economy flag of the new kind
Contraband, shown with the other flags and in the character's related data. Items marked for
removal are taken away, with a character snapshot kept first so they can be given back, an audit
entry and a mail or chat message telling the player why. Staff are skipped unless
contraband_ignore_staff is off. Worlds reload the list when it changes (RELOAD_CONTRABAND, added
at the end of ePlayerAction).

Fixes #1563

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

migrations/dlu/mysql/77_contraband.sql

@@ -0,0 +1,9 @@
+/* Contraband: items staff don't want players to have, edited on the dashboard's Contraband page. action: 0 = flag
+   (an economy flag of kind 5 when a character has one), 1 = flag and remove the item. */
+CREATE TABLE IF NOT EXISTS contraband_items (
+    lot INT NOT NULL PRIMARY KEY,
+    reason TEXT NOT NULL,
+    action TINYINT NOT NULL DEFAULT 0,
+    added_by VARCHAR(64) NOT NULL DEFAULT '',
+    added_at BIGINT NOT NULL DEFAULT 0
+);

migrations/dlu/sqlite/60_contraband.sql

@@ -0,0 +1,8 @@
+/* contraband_items: see the MySQL migration. */
+CREATE TABLE IF NOT EXISTS contraband_items (
+	lot INTEGER NOT NULL PRIMARY KEY,
+	reason TEXT NOT NULL,
+	action INTEGER NOT NULL DEFAULT 0,
+	added_by TEXT NOT NULL DEFAULT '',
+	added_at BIGINT NOT NULL DEFAULT 0
+);