houses: nightly Kamernet + Vesteda scraper, dedupe by address, owner-only /trackers/houses

- scripts/house-scrape.ts: polite nightly scrape (honest UA, 6-10 s apart, stops a source on 403/challenge), ingest + price history + removals, ntfy alerts on a separate topic (max 5 + summary, first run seeds)
- address_key + duplicate_of: copies on another source link to one listing, manual wins
- /projects/house-tracker -> /trackers/houses (308), owner only (404 otherwise); filters for min m2, rooms, source, Gouda region default; notes, add-by-hand form, total rent, also-on links
- scripts/house-db.sh: run the house-listing CLI as the limited house_cli role
- deploy/systemd/house-scrape.{service,timer}

deploy/systemd/house-scrape.service

@@ -0,0 +1,13 @@
+[Unit]
+Description=House tracker nightly scrape (Kamernet, Vesteda -> house.listings)
+Wants=network-online.target
+After=network-online.target
+
+[Service]
+Type=oneshot
+# A checkout of stan/website on main. Not the live dev tree.
+WorkingDirectory=%h/dev/website-houses
+# DB_URL (house_scraper role: house schema only), optional HOUSE_NTFY_URL; mode 600, never committed.
+EnvironmentFile=%h/.config/house-scrape.env
+ExecStart=/usr/bin/bun scripts/house-scrape.ts
+TimeoutStartSec=900