chore(ai): remove dead code (agent)

Removed unused exports and functions identified as dead code.
- Removed unused exports from `js/utils/storage.js`, `js/utils/storagePointer.js`, `js/utils/videoTags.js`, `js/ui/moderationCopy.js`.
- Removed unused function `updateTagPillStrip` from `js/ui/components/tagPillList.js` and associated tests.
- Updated `tests/utils/video-tags.test.mjs` to remove test for private function.
- Added `artifacts/depcheck.json` showing dependency analysis.
- Fixed unit test mock for `ProfileModalController` to include `hashtagPreferencesService.load`.

Co-authored-by: PR0M3TH3AN <[email protected]>

tests/profile-modal-controller.test.mjs

@@ -274,6 +274,7 @@ function createController(options = {}) {
       return hashtagStore.disinterests.delete(normalized);
     },
     publish: async () => ({ ok: true }),
+    load: async () => {},
     on: () => () => {},
   };