Add California police feeds for cities over 50,000 residents

[ralyodio]

The crime collection currently misses local police announcements that are published outside open-data portals. Add hourly ingestion from 35 public Nixle archives and four police RSS feeds, plus a California source directory covering all 177 incorporated cities with more than 50,000 residents in Census Vintage 2025. The directory also supports a 100,000 population filter. No paid API or social login is required.

The 39 reviewed publishers are explicitly enabled; the other 138 cities retain reference links and are shown as needing a feed. Discovery candidates, stale archives and broad county publishers never activate themselves. Announcements use the separate police-update kind, publisher timestamps and clearly labelled city reference points, so they work with radius queries without entering incident-only feeds or implying exact incident locations.

• Adds /c/crime/coverage, /f/police-updates-ca, hourly source seeds, and location/time explanations on records.
• Bounds Nixle detail reads, rechecks the latest two posts for corrections, respects robots access rules and preserves retries after failures.
• Includes state/population discovery scripts, provenance, format/freshness audits and reproducible review instructions in docs/police-sources.md. Most of the diff is generated source inventory data.
• Normal startup seeds the sources. No migration is required; deployment is still needed for the public site.

Validation: all 39 live adapter checks passed and returned 75 dated items; 1,616 Bun tests passed with one local PostgreSQL migration test skipped; eight Python discovery checks passed; lint passed with existing warnings. Geographic integration tests verify the original California radius query and exclusion from incident-only feeds.