feat: manual EPG-to-channel mapping with mapping fallback (#1165)

* feat(epg): manual EPG-to-channel mapping with mapping fallback in all EPG paths

* fix: epg mapping in live tv list

* fix(epg): harden manual EPG mapping — upgrade safety, perf, playlist-scoped keys

Follow-up fixes on top of the manual EPG-to-channel mapping feature:

- epg-database: dedupe existing epg_programs rows before creating the
  unique (channel_id, start, title) index — a plain CREATE UNIQUE INDEX
  crashed the EPG worker on upgrade when historical duplicates exist;
  replace INSERT OR REPLACE with ON CONFLICT DO UPDATE so the
  epg_programs_fts delete trigger is not bypassed (REPLACE skips delete
  triggers unless recursive_triggers is on), with a plain-INSERT
  fallback when the index cannot be created
- db: add idx_content_epg_channel — the mapping fallback scanned the
  whole content table on every single-channel EPG lookup
- keys: scope Xtream mapping keys per playlist via shared
  buildXtreamEpgMappingKey (xtream:{playlistId}:{id}) — bare stream ids
  collide across portals; the backend fallback now joins categories to
  resolve the playlist id
- pwa: hide "Map EPG channel" entries behind the supportsEpgMapping
  capability — the menu item was a dead end in the PWA
- parser: parse the XMLTV offset sign from the string — Math.sign(0)
  dropped the minutes of ±00:xx offsets
- cleanup: typed window.electron access instead of ad-hoc casts, drop
  unused resolveChannelId and dialog data field, shared
  EpgMappingDialogComponent.open() for all seven call sites
- dialog UX: minimum-characters search hint, save/remove snackbars,
  current mapping shows the EPG channel display name,
  takeUntilDestroyed on the search stream
- i18n: fill the new keys in all 17 locales
- tests: cover mapping CRUD/search escaping, the dedup-index guard,
  offset parsing and playlist-scoped keys; update stale stream-resolver
  specs for the new 50-item limit and 10s timeout

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* fix(epg): escape backslashes in EPG channel search LIKE pattern

CodeQL js/incomplete-sanitization: a lone trailing backslash in the
search term paired with the closing wildcard under the ESCAPE clause
and corrupted the pattern.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* perf(epg): batch mapping lookups in the viewport preview queue

Expose the existing getEpgMappingsBatch operation over a new
EPG_MAPPING_GET_BATCH IPC channel and use it in resolveManualMappings —
the per-entry lookup issued one IPC round-trip per visible channel on
every scroll event.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* perf(epg): batch mapping prefetch in the collection preview loader

Resolve all candidate mapping keys for an Xtream preview batch with a
single getEpgMappingsBatch IPC call instead of per-channel lookups.
Also fix a worker early-exit: a channel without tvgId/name returned out
of the shared-iterator loop and silently killed one of the three
concurrent preview workers.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

---------

Co-authored-by: 4gray <serega05@gmail.com>
Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

libs/shared/database/src/lib/connection.ts

@@ -169,6 +169,7 @@ const CREATE_TABLE_STATEMENTS = [
     `CREATE INDEX IF NOT EXISTS idx_categories_playlist ON categories(playlist_id)`,
     `CREATE INDEX IF NOT EXISTS idx_content_title ON content(title)`,
     `CREATE INDEX IF NOT EXISTS idx_content_xtream ON content(xtream_id)`,
+    `CREATE INDEX IF NOT EXISTS idx_content_epg_channel ON content(epg_channel_id)`,
     `CREATE INDEX IF NOT EXISTS idx_content_type_added ON content(type, added)`,
     `CREATE INDEX IF NOT EXISTS idx_categories_type ON categories(type)`,
     // Partial covering index for visible categories — supports the dashboard's
@@ -261,6 +262,15 @@ const CREATE_TABLE_STATEMENTS = [
       INSERT INTO epg_programs_fts(rowid, title, description, category)
       VALUES (new.id, new.title, new.description, new.category);
   END`,
+    // EPG channel mappings (manual user overrides)
+    `CREATE TABLE IF NOT EXISTS epg_channel_mappings (
+      id INTEGER PRIMARY KEY AUTOINCREMENT,
+      channel_key TEXT NOT NULL UNIQUE,
+      epg_channel_id TEXT NOT NULL,
+      playlist_id TEXT,
+      updated_at TEXT DEFAULT (datetime('now'))
+  )`,
+    `CREATE INDEX IF NOT EXISTS idx_epg_channel_mappings_playlist ON epg_channel_mappings(playlist_id)`,
     // Playback Positions table
     `CREATE TABLE IF NOT EXISTS playback_positions (
       id INTEGER PRIMARY KEY AUTOINCREMENT,

libs/shared/database/src/lib/schema.ts

@@ -110,6 +110,9 @@ export const content = sqliteTable(
         categoryIdx: index('idx_content_category').on(table.categoryId),
         titleIdx: index('idx_content_title').on(table.title),
         xtreamIdx: index('idx_content_xtream').on(table.xtreamId),
+        epgChannelIdx: index('idx_content_epg_channel').on(
+            table.epgChannelId
+        ),
         categoryTypeXtreamUnique: uniqueIndex(
             'content_category_type_xtream_unique'
         ).on(table.categoryId, table.type, table.xtreamId),
@@ -347,6 +350,26 @@ export const downloads = sqliteTable(
     })
 );
 
+// EPG channel mappings (manual user overrides)
+export const epgChannelMappings = sqliteTable(
+    'epg_channel_mappings',
+    {
+        id: integer('id').primaryKey({ autoIncrement: true }),
+        channelKey: text('channel_key').notNull().unique(),
+        epgChannelId: text('epg_channel_id').notNull(),
+        playlistId: text('playlist_id'),
+        updatedAt: text('updated_at').default(sql`CURRENT_TIMESTAMP`),
+    },
+    (table) => ({
+        playlistIdx: index('idx_epg_channel_mappings_playlist').on(
+            table.playlistId
+        ),
+    })
+);
+
+export type EpgChannelMapping = typeof epgChannelMappings.$inferSelect;
+export type NewEpgChannelMapping = typeof epgChannelMappings.$inferInsert;
+
 export type Download = typeof downloads.$inferSelect;
 export type NewDownload = typeof downloads.$inferInsert;