fix(m3u): honor DASH catch-up URLs and drop unusable DRM fallbacks

Two Codex round-2 findings:

- The inline-playback DASH gate only examined the channel URL, while the
  external-player guard checks the resolved catch-up URL — a replay that
  resolves to an .mpd manifest with MPV/VLC configured ended up with no
  player at all. The gate now uses the effective playback URL
  (activePlaybackUrl ?? channel.url).
- The unsupported-DRM diagnostic advertised MPV/VLC fallback actions,
  but external players cannot receive the KODIPROP license config either
  — the diagnostic no longer recommends them.

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

libs/ui/playback/src/lib/playback-diagnostics/playback-diagnostics.util.ts

@@ -237,6 +237,9 @@ export function createPlaybackDiagnostic(options: {
     readonly details?: string;
     readonly nativeErrorCode?: number;
     readonly nativeErrorMessage?: string;
+    /** Overrides the code-derived recommendation, e.g. when external players
+     * are known to be unable to handle the stream either. */
+    readonly externalFallbackRecommended?: boolean;
 }): PlaybackDiagnostic {
     const {
         code,
@@ -259,7 +262,9 @@ export function createPlaybackDiagnostic(options: {
         details: details || undefined,
         nativeErrorCode,
         nativeErrorMessage,
-        externalFallbackRecommended: isExternalFallbackRecommended(code),
+        externalFallbackRecommended:
+            options.externalFallbackRecommended ??
+            isExternalFallbackRecommended(code),
     };
 }
 

libs/ui/playback/src/lib/shaka-engine/shaka-error-classifier.spec.ts

@@ -86,7 +86,7 @@ describe('classifyShakaPlaybackIssue', () => {
 });
 
 describe('createUnsupportedDrmDiagnostic', () => {
-    it('creates a DRM diagnostic carrying the license type', () => {
+    it('creates a DRM diagnostic without recommending unusable external fallbacks', () => {
         const issue = createUnsupportedDrmDiagnostic(
             'com.widevine.alpha',
             metadata
@@ -94,6 +94,8 @@ describe('createUnsupportedDrmDiagnostic', () => {
         expect(issue.code).toBe(PlaybackDiagnosticCode.DrmOrEncryption);
         expect(issue.source).toBe(PlaybackDiagnosticSource.Shaka);
         expect(issue.details).toContain('com.widevine.alpha');
-        expect(issue.externalFallbackRecommended).toBe(true);
+        // MPV/VLC cannot receive KODIPROP license config, so the diagnostic
+        // must not offer them as a fallback.
+        expect(issue.externalFallbackRecommended).toBe(false);
     });
 });

libs/ui/playback/src/lib/shaka-engine/shaka-error-classifier.ts

@@ -111,6 +111,9 @@ export function createUnsupportedDrmDiagnostic(
         details: licenseType
             ? `Unsupported DRM license configuration: ${licenseType}`
             : 'Unsupported DRM license configuration',
+        // External MPV/VLC cannot receive the KODIPROP license config either,
+        // so offering them as a fallback would just fail differently.
+        externalFallbackRecommended: false,
     });
 }