v0.16.1 — fixes from an external code review

[0.16.1] — 2026-06-14 — Fixes from an external code review

Fixed

• --db now controls ALL persistence for LLM scrapers. Previously a fetch
  through core.run_fetch(store=...) saved the OPPORTUNITIES on the caller's DB but
  the LLM extraction cache + the crawl recipe store on a DEFAULT/BANDIRADAR_DB DB
  (the scraper opened its own Store(None)). core now threads the caller's store
  into an LLM source's fetch (requires_llm sources only), binding the extraction
  cache + recipe store to the same DB. (The production monitor was unaffected — it
  points BANDIRADAR_DB at its state DB so both resolved to the same file — but the
  --db flag was leaky.)
• validate_refs now requires a non-empty post_id. A crawl ref with a url +
  title but a None/empty post_id was counted as "usable", yet post_id builds
  RawDoc.id/Opportunity.id downstream — so it would collide as source:None. Such
  a ref is now treated as drift (the listing's id field moved), surfacing via crawl
  health instead of producing colliding ids.
• Reproducible Quickstart. --sample runs now pin the reference time to a fixed
  core.SAMPLE_NOW (2026-06-08, the fixtures' capture date), so the demo output no
  longer drifts as the calendar moves (bundled fixtures have fixed deadlines; items
  were silently "closing" over time). The README's match output is regenerated to the
  reproducible result and documents the pin.