v0.9.0 — AOI geofences become a continuous watch

AOI geofences become a continuous watch: the collector daemon sweeps
every defined area on its interval, and a webhook fires when something
enters or leaves.

Added

• Scheduled AOI sweeps: aoi_digest is now a collector source
  (analysis.aoi.fetch_aoi_sweep, a fetcher-only wrapper that opens
  the AOI store on the fetcher's own cache database), so
  intel-collector --daemon advances every defined geofence's change
  snapshot on each cycle - the daemon interval is the watch cadence,
  and the existing launchd wrapper makes it survive reboots. New aoi
  domain group for --sources aoi. Digests land in the collector log
  and the vector store, and in the webhook below when configured.
• AOI change notifications: set WORLD_INTEL_AOI_WEBHOOK and the
  sweep POSTs every non-quiet digest (something entered or left a
  geofence) to that URL - json payload by default
  (title/totals/markdown/timestamp), or raw markdown with a Title
  header via WORLD_INTEL_AOI_WEBHOOK_FORMAT=text for ntfy-style
  sinks. Quiet sweeps never fire; an unreachable sink or non-2xx
  response never fails the sweep (snapshots already advanced) but is
  recorded honestly in the digest's notification field. New
  Fetcher.post() carries the delivery - deliberately outside the
  caching/retry/breaker machinery, since the target is the operator's
  own endpoint. Live-verified end-to-end against a local sink: a real
  sweep detected a change and the sink received the JSON payload.
• Per-source collector timeout overrides (SOURCE_TIMEOUTS): a live
  smoke caught a single 50 km AOI sweep on a cold cache blowing the
  flat 45 s budget (the digest fans out to ~8 domains per AOI, several
  rate-floored); the sweep now gets 240 s and the override path is
  regression-tested.