v1.0.9-beta.004 - feat(calendar): implement hybrid release calendar engine
This complete overhaul of the release calendar and series monitor introduces a two-phase hybrid approach to populate future release dates accurately without triggering ComicVine API rate limits.
- Implement Metron Oracle (Phase 1) to fetch a global 90-day window of upcoming releases, matching them locally via exact Metron IDs or fuzzy string matching (Name + Publisher) for CV-sourced series.
- Add 429 rate-limit backoff (15s) for Metron API requests.
- Implement Slow-Drip ComicVine fallback (Phase 2) to safely cycle through the 25 oldest monitored CV series per run, ensuring manga and obscure indies are caught without triggering IP bans.
- Remove the monitored: true restriction from /api/calendar/route.ts so the calendar populates upcoming dates for the entire library.
- Fix cover image logic in the Calendar API to correctly serve external HTTP URLs directly while proxying local disk images.
- Update calendar UI (page.tsx) to group issues by Month/Year, format exact release days, and update empty-state copy to reflect library-wide scanning.
Resolves #86