Add setting to hide YouTube AI-labeled videos across feeds (#4254)

[FaiziNerd]

Summary

• Adds a General setting Hide AI-labeled videos for issue 💡Hide AI videos #4254
• Detects YouTube AI disclosure labels on watch/Shorts pages, remembers video IDs, and hides those items across home/related/search/feeds
• Includes Clear remembered AI videos, EN locale strings, and page-world injection wiring

How it works

YouTube often shows AI labels only after opening a video (not on every thumbnail). This feature:

1. Detects the AI label on watch/Shorts
2. Remembers the video ID in storage
3. Hides that video site-wide in feeds (blocklist-style class marking + CSS)
4. Also hides cards that already show a “Made with AI” / “Altered or synthetic” badge when present

Bug fixes included

• Avoid false positives from generic phrases like “How this content was made” (also used for camera disclosures)
• Avoid matching bare “AI” text outside badge/button contexts under the player/Shorts overlay
• Ignore stale ytInitialPlayerResponse when its videoId does not match the current video (SPA navigations)

Known limitation

First-time AI videos may still appear until identified once; afterward they stay hidden across pages.

Test plan

• Load unpacked extension and enable Hide AI-labeled videos
• Open a watch page with a visible AI label → video ID is remembered
• Confirm that video is hidden on home, related/suggested, and search
• Open a non-AI video → it is not hidden
• Toggle the setting off → items become visible again
• Use Clear remembered AI videos → list resets
• Navigate between videos (SPA) and confirm non-AI videos are not wrongly marked

Closes #4254