feat: house tracker with home worker, alerts and listing map

Collects Pararius rent/buy listings into Postgres via a worker that runs on a
residential connection, sends Discord/ntfy alerts for new listings matching
rules, and shows an admin-only map, market stats and worker log.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_013HfF5tnChi8tkCx9svJP6D

.env.example

@@ -28,3 +28,10 @@ R2_ACCESS_KEY_ID=
 R2_SECRET_ACCESS_KEY=
 R2_BUCKET=
 R2_PUBLIC_URL=
+
+# House tracker: shared secret for the home worker (openssl rand -hex 32), and
+# where alerts go (Discord webhook and/or ntfy topic URL). See docs/house-tracker.md.
+HOUSE_WORKER_TOKEN=
+HOUSE_DISCORD_WEBHOOK_URL=
+HOUSE_NTFY_URL=
+HOUSE_NTFY_TOKEN=