fix(services/spotlight): improve MPRIS artwork handling and scope keyword searches to single plugin

- mpris: native MediaArt cache lookup, dedupe play/pause emission, safe
  cleanup, artwork polling for already-playing browser players, drop
  os.system seek fallback
- spotlight: scope plugin keyword and detect() matches to a single plugin
  via search_single instead of global search; register clipboard keywords
  (clip/clipboard)

.github/workflows/codeql.yml

@@ -2,9 +2,9 @@ name: CodeQL
 
 on:
   push:
-    branches: [main]
+    branches: [main, dev]
   pull_request:
-    branches: [main]
+    branches: [main, dev]
   schedule:
     - cron: "0 6 * * 1"