feat(epg): manual EPG mapping for Stalker portals (#1173)

* feat(epg): manual EPG mapping for Stalker portals

Extends the manual EPG-to-channel mapping (PR #1165) to Stalker:

- shared key helper buildStalkerEpgMappingKey — playlist-scoped
  stalker:{playlistId}:{channelId} keys, mirroring the Xtream scheme
- ITV sidebar: right-click context menu with "Map EPG channel"; after
  the dialog closes with a change, the bulk EPG cache is rebuilt so the
  panel and row previews reflect the new mapping immediately
- withStalkerEpg().applyMappedItvEpg(): batch-resolves mappings for
  rendered channels (one getEpgMappingsBatch IPC per new id set) and
  overlays uploaded-XMLTV programs onto bulkItvEpgByChannel; overrides
  survive ensureBulkItvEpg reloads
- stream-resolver: mapping check in loadStalkerEpgItems (detail) and
  batched prefetch in loadStalkerEpgBatch (previews);
  mappingCandidateKeys/prefetchEpgMappings generalized beyond Xtream
- global favorites: stalker branch for the Map-EPG menu entry (item id
  extracted from the stalker::{playlistId}::{id} uid)
- docs: manual-mapping section in docs/architecture/stalker-epg.md and
  a CLAUDE.md EPG bullet covering the whole mapping feature
- tests: applyMappedItvEpg suite, stalker preview mapping in the
  stream-resolver spec, key-builder specs

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

* fix(epg): harden Stalker mapping edges found in adversarial review

- stream-resolver: stalker items resolve only the playlist-scoped
  mapping key — bare tvgId/name candidates (tvgId mirrors the raw
  provider id) could only produce false matches against unrelated M3U
  mappings, and previews would disagree with the detail path
- applyMappedItvEpg: staleness guard after every await so an in-flight
  call cannot write portal A's mapped EPG into portal B's state after
  a playlist switch (the store is a root singleton)
- applyMappedItvEpg: ids are marked checked only after a successful
  lookup — a transient IPC failure no longer suppresses the mapping
  for the rest of the session
- live layout: post-dialog refresh re-applies overrides for the
  unfiltered channel list, so an active search cannot drop the playing
  channel's mapping
- global favorites: new epgMappingChanged output emitted when the
  dialog actually changed a mapping; unified live tab reloads its EPG
  previews in response

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

---------

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

libs/shared/interfaces/src/lib/epg-mapping-key.util.spec.ts

@@ -1,4 +1,7 @@
-import { buildXtreamEpgMappingKey } from './epg-mapping-key.util';
+import {
+    buildStalkerEpgMappingKey,
+    buildXtreamEpgMappingKey,
+} from './epg-mapping-key.util';
 
 describe('buildXtreamEpgMappingKey', () => {
     it('scopes the key to the playlist', () => {
@@ -19,3 +22,17 @@ describe('buildXtreamEpgMappingKey', () => {
         );
     });
 });
+
+describe('buildStalkerEpgMappingKey', () => {
+    it('scopes the key to the playlist', () => {
+        expect(buildStalkerEpgMappingKey('portal-a', '205')).toBe(
+            'stalker:portal-a:205'
+        );
+    });
+
+    it('never collides with the Xtream key space', () => {
+        expect(buildStalkerEpgMappingKey('p', 1)).not.toBe(
+            buildXtreamEpgMappingKey('p', 1)
+        );
+    });
+});

libs/shared/interfaces/src/lib/epg-mapping-key.util.ts

@@ -6,11 +6,11 @@
  * channel name) directly — those identifiers are meaningful across
  * playlists, so a mapping saved once applies everywhere.
  *
- * Xtream stream IDs, on the other hand, are provider-local integers:
- * stream 12345 in portal A has nothing to do with stream 12345 in
- * portal B. Mapping keys for Xtream channels therefore embed the
- * playlist ID so mappings never leak across portals. Shared between the
- * renderer and the Electron main process/worker, like
+ * Xtream stream IDs and Stalker channel IDs, on the other hand, are
+ * provider-local: stream 12345 in portal A has nothing to do with
+ * stream 12345 in portal B. Mapping keys for portal channels therefore
+ * embed the playlist ID so mappings never leak across portals. Shared
+ * between the renderer and the Electron main process/worker, like
  * `title-normalization.util.ts`.
  */
 export function buildXtreamEpgMappingKey(
@@ -19,3 +19,10 @@ export function buildXtreamEpgMappingKey(
 ): string {
     return `xtream:${playlistId}:${xtreamId}`;
 }
+
+export function buildStalkerEpgMappingKey(
+    playlistId: string,
+    stalkerId: number | string
+): string {
+    return `stalker:${playlistId}:${stalkerId}`;
+}