v0.3.0 — URL feed loading + calendar-analytics fixes

Added

• Load a GTFS feed directly from a URL (#45): the browser fetches the feed client-side — no backend, and the feed data stays on the device. Works for CORS-enabled hosts such as the Mobility Database catalog; other hosts fall back cleanly to download-and-drop.
• Run-to-run comparison page (#21): compare the current feed against an older Golden JSON — fixed/new/increased/decreased rules, score, severity, class, feed-size, date-range and normalized notice-density deltas.
• Golden JSON v4 with a UTC generated_at, file row/byte counts, feed metrics, analysis settings, rule metadata and severity/class totals. Golden v1–v3 remain importable with marked limitations.

Changed

• The downloaded Golden snapshot is byte-deterministic again for git-tracked regression baselines (#42): it omits the per-second generated_at while keeping the day-granular validate_date; the in-app comparison keeps its live timestamp.
• CAL_006 (all weekday columns are 0) and RTS_020 (route_url equals agency_url) are now Info, matching MobilityData; CAL_006 is reframed as a dates-only hint rather than "service never runs".
• The Memory64 package (pkg64) is now optimized with wasm-opt (~2.37 MB → ~2.02 MB).

Fixed

• STP_021 no longer flags valid Entrance/Exit stops. It now targets Boarding Areas (location_type=4) that lack a platform parent, removing high-severity false positives (e.g. 132 on the BART feed) that skewed the quality score.
• Calendar-analytics over-fire on feeds that model one operational calendar as many service-id variants (#30): CAL_007/CAL_012 gaps and CAL_013 expiries are aggregated by signature, so each is reported once with the affected services listed.