feat: schedule ingestion — real data 24/7

[Kwickos]

Fills the API with real data even when no game is live.

Added

• ScheduledMatch domain type + LolFeedAdapter.fetch_schedule() (getSchedule endpoint).
• Repository.upsert_schedule(): idempotent upsert of leagues + matches (status refresh on re-poll).
• SchedulePoller (default every 5 min) run alongside LiveGameTracker in the worker and in RUN_WORKER_IN_API mode.
• Tests: insert + idempotent status update.

Verified

• ruff clean · pytest 14/14 · real run: 80 matches / 8 leagues (EMEA Masters, LCK, LCS, LJL, LPL, LRN, LRS, VCS) ingested from the live schedule into SQLite.