feat(04-02): Overpass top-up proposer (D-06) + JSON-to-SQLite converter (D-05)

overpass-topup.mjs — maintainer-time repo tool, six hard laws:
- never imported by bot/src or web/src (TP1 gate); Worker reads only the committed JSON
- exactly ONE request per run: both live paths (Overpass POST, Nominatim GET)
  share a single requestJson helper — one fetch( call site (TP7)
- identifying User-Agent araharah-gazetteer-topup/1.0 mandatory (missing UA = HTTP 406)
- busy/saturated/unusable response -> 'Overpass instance busy — retry later', exit 0 (TP4)
- output is a PROPOSAL only; source never names the curated file, so it cannot write it (TP6)
- --source=overpass|nominatim|fixture (--fixture implies fixture), --endpoint/OVERPASS_ENDPOINT
  override, bbox-bounded single-family query pinned verbatim (3.05,101.55,3.25,101.80) (TP3)
- --fixture selects the offline path by itself (a fixture flag silently hitting the
  live network would be a trap — fixed during GREEN)

overpass-response.json — committed real-shape Overpass response (6 KL elements:
nodes with lat/lon, ways/relation with center) so the test is deterministic.

json-to-sqlite.mjs — backend #2's dataset format reachable today (D-05):
- reads the same committed kl-gazetteer.json, emits kl-gazetteer.sqlite via
  node:sqlite (zero added deps) with the SAME id set (CV1), plus the ODbL
  notice embedded in a metadata table + NOTICE sidecar (ODbL s4.4, T-04-20)
- deterministic: rows in dataset order, no timestamps

search/test/fixtures/overpass-response.json

@@ -0,0 +1,88 @@
+{
+  "version": 0.6,
+  "generator": "Overpass API 0.7.62.7",
+  "osm3s": {
+    "timestamp_osm_base": "2026-10-23T14:55:20Z",
+    "copyright": "The data included in this document is from www.openstreetmap.org. The data is made available under ODbL."
+  },
+  "elements": [
+    {
+      "type": "way",
+      "id": 23034336,
+      "center": { "lat": 3.1408, "lon": 101.7047 },
+      "tags": {
+        "name": "Merdeka 118",
+        "name:en": "Merdeka 118",
+        "building": "yes",
+        "building:levels": "118",
+        "height": "678.9",
+        "tourism": "attraction",
+        "wikidata": "Q18166176"
+      }
+    },
+    {
+      "type": "way",
+      "id": 12345678,
+      "center": { "lat": 3.1489, "lon": 101.6936 },
+      "tags": {
+        "name": "National Monument",
+        "name:en": "National Monument",
+        "alt_name": "Tugu Negara",
+        "historic": "memorial",
+        "tourism": "attraction"
+      }
+    },
+    {
+      "type": "node",
+      "id": 87654321,
+      "lat": 3.1484,
+      "lon": 101.6953,
+      "tags": {
+        "name": "Masjid Jamek",
+        "name:en": "Jamek Mosque",
+        "amenity": "place_of_worship",
+        "religion": "muslim",
+        "tourism": "attraction",
+        "wikidata": "Q2713345"
+      }
+    },
+    {
+      "type": "way",
+      "id": 34567123,
+      "center": { "lat": 3.1528, "lon": 101.7038 },
+      "tags": {
+        "name": "Kuala Lumpur Tower",
+        "name:en": "Kuala Lumpur Tower",
+        "short_name": "KL Tower",
+        "man_made": "tower",
+        "tourism": "attraction",
+        "wikidata": "Q265917"
+      }
+    },
+    {
+      "type": "way",
+      "id": 45678123,
+      "center": { "lat": 3.1454, "lon": 101.6953 },
+      "tags": {
+        "name": "Central Market",
+        "name:en": "Central Market",
+        "alt_name": "Pasar Seni",
+        "building": "retail",
+        "tourism": "attraction",
+        "wikidata": "Q5061407"
+      }
+    },
+    {
+      "type": "relation",
+      "id": 56781234,
+      "center": { "lat": 3.1436, "lon": 101.6975 },
+      "tags": {
+        "name": "Petaling Street",
+        "name:en": "Petaling Street",
+        "highway": "pedestrian",
+        "tourism": "attraction",
+        "wikidata": "Q1985815"
+      }
+    }
+  ]
+}