Video & Podcast Studio Search Fix, FTS5 Self-Healing & Atomic GCS Snapshots

• 🎬 Studio Search Query Parsing & Top-Level HTTP 500 Guardrail: Fixed an unhandled NameError in GET /api/studio/search and added a top-level request exception boundary across all HTTP verbs so route errors never drop raw TCP sockets.
• 🛡️ Atomic SQLite Online Backups, GCS Versioning & FTS5 Self-Healing: Switched GCS snapshots to SQLite's online backup API with pre-upload verification, enabled point-in-time GCS Object Versioning with automatic healthy-generation fallback, and added lossless FTS5 self-recovery.
• ⚡ Sub-Second Warm Startups & Bounded Worker Pools: Measured actual unmerged FTS5 B-tree segments (articles_fts_idx), eliminated duplicate startup DB initialization, and routed background feed crawls and AT Protocol PDS syncs through bounded worker pools with per-user OAuth refresh locking.
• 🚦 Pre-Deploy Static/Test Gate & Deep /api/healthz Probes: Gated deployments on undefined-name symbol analysis and the full test suite, backed by Cloud Run SQLite/FTS5 /api/healthz startup/liveness probes and automatic post-deploy smoke rollback.
• 🔗 Instant Shared Items GCS Journal & Non-Throttled Snapshot Uploads: Added sub-second shared_items_backup.json GCS journaling with startup replay, 16 MiB chunked snapshot uploads, immediate tmpfs cleanup, and unthrottled Cloud Run background CPU so shared posts and public curator RSS feeds never roll back across container restarts.
• 🌐 www.webnerd.ai Custom Domain & Canonical Redirect: Provisioned the Cloudflare Workers Custom Domain and edge TLS certificate for www.webnerd.ai on webnerd-proxy with 301 canonical redirection to https://webnerd.ai.
• ▶️ Live YouTube Data API v3 Subscription Sync & CSV/OPML Upload: Enabled youtube.googleapis.com on webnerd-rss, fixed the OAuth token callback race in triggerStudioYouTubeSync so real YouTube subscriptions sync without premature fallback catalog pollution, added live @handle RSS resolution, and added 1-click Google Takeout CSV / OPML file upload in the Studio.
• 📜 Terms of Service (/terms) & Google OAuth / YouTube API Policy Disclosures: Added a dedicated Terms of Service page at /terms, added Google API Services User Data Policy (Limited Use) and YouTube API Services disclosures on /privacy, and added visible homepage footer links to /privacy and /terms.