Municipals: nest 1,823 city officeholders under their real counties

Pull Atlas's place→county crosswalk (Census TIGER 2024 places × county
geometries, 32,041 places) into the build as a committed raw input, and
use it to resolve municipal officeholders whose county was unknown.

- data/place_county_crosswalk.jsonl — new raw input (place_geoid → county_geoid)
- build.py — place-name+state → county_geoid → ACS county slug as a fallback
  in county_slug(); city_slug() generalized to non-FL bare place labels
- data/sources/sources.yaml — provenance entry for the crosswalk

_unresolved municipals: 1919 → 58. The remainder are genuine: CT planning
regions (post-county), county-level rows mislabeled municipal upstream,
consolidated city-counties (null label), Wikidata-QID placeholder names,
and ambiguous same-name places — left unresolved rather than guessed.

Join key is county_geoid (5-digit FIPS); the directory slug is taken from
the ACS county node so municipals nest under the exact existing county dir.
Deterministic (byte-identical rebuild); validate.py passes 19,721 records.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

data/jurisdictions/us/states/nj/counties/middlesex/index.md

@@ -32,7 +32,7 @@ timestamp: "2026-07-03"
 
 # Middlesex County, NJ
 
-County jurisdiction.
+County jurisdiction — 3 officeholders mapped.
 
 ## Demographics (ACS 2023)
 

data/jurisdictions/us/states/nj/counties/middlesex/municipalities/new-brunswick/people/jim-cahill.md

@@ -0,0 +1,39 @@
+---
+type: Person
+title: "Jim Cahill"
+description: "Mayor, New Brunswick, NJ"
+role: "Mayor, New Brunswick, NJ"
+level: "municipal"
+branch: "executive"
+state: "NJ"
+tenure:
+  start: "2026-06-20"
+  current: true
+ids:
+  person: "517b9b69-7a9a-4c56-982c-9a242fa0a567"
+  office: "d694bb8f-0716-49c6-bfe8-ac1e6fc90d9e"
+  tenure: "692a07fe-6229-4161-b465-d53d82d13888"
+  jurisdiction: "ed9fdb2c-c4bb-4e2e-b32c-2a349782c6c3"
+sources:
+  - field: office
+    source: "Wikidata"
+  - field: tenure
+    source: "Wikidata"
+  - field: jurisdiction
+    source: "Census TIGER 2024"
+confidence: official
+tags: [officeholder, municipal, executive, nj]
+timestamp: "2026-07-04"
+---
+
+# Jim Cahill
+
+Current Mayor, New Brunswick, NJ.
+
+## Sources
+
+- office: Wikidata
+- tenure: Wikidata
+- jurisdiction: Census TIGER 2024
+
+Generated from the Atlas officeholders v3 export (2026-07-04).

data/jurisdictions/us/states/nj/counties/middlesex/municipalities/perth-amboy/people/helmin-j-caba.md

@@ -0,0 +1,39 @@
+---
+type: Person
+title: "Helmin J. Caba"
+description: "Mayor, Perth Amboy, NJ"
+role: "Mayor, Perth Amboy, NJ"
+level: "municipal"
+branch: "executive"
+state: "NJ"
+tenure:
+  start: "2026-06-20"
+  current: true
+ids:
+  person: "edf5eab8-4e4c-4a10-a5f0-31d1756f6541"
+  office: "787b76d2-c722-493b-a3af-ecfa6d72d25f"
+  tenure: "56b30c90-39df-4f40-a26c-0803d82deb22"
+  jurisdiction: "af88e47b-f418-4ce9-b691-d2b916eed8ad"
+sources:
+  - field: office
+    source: "Wikidata"
+  - field: tenure
+    source: "Wikidata"
+  - field: jurisdiction
+    source: "Census TIGER 2024"
+confidence: official
+tags: [officeholder, municipal, executive, nj]
+timestamp: "2026-07-04"
+---
+
+# Helmin J. Caba
+
+Current Mayor, Perth Amboy, NJ.
+
+## Sources
+
+- office: Wikidata
+- tenure: Wikidata
+- jurisdiction: Census TIGER 2024
+
+Generated from the Atlas officeholders v3 export (2026-07-04).

data/jurisdictions/us/states/nj/counties/middlesex/municipalities/south-amboy/people/fred-a-henry.md

@@ -0,0 +1,39 @@
+---
+type: Person
+title: "Fred A. Henry"
+description: "Mayor, South Amboy, NJ"
+role: "Mayor, South Amboy, NJ"
+level: "municipal"
+branch: "executive"
+state: "NJ"
+tenure:
+  start: "2026-06-20"
+  current: true
+ids:
+  person: "43ee4482-d905-4022-8832-9bdaa5803aa6"
+  office: "6e5e256f-0c09-49e1-85a8-df989473f639"
+  tenure: "3522f114-8d07-4f0f-8491-ee93e8728f3c"
+  jurisdiction: "2e31686d-952f-4be6-b6a0-abfd52796056"
+sources:
+  - field: office
+    source: "Wikidata"
+  - field: tenure
+    source: "Wikidata"
+  - field: jurisdiction
+    source: "Census TIGER 2024"
+confidence: official
+tags: [officeholder, municipal, executive, nj]
+timestamp: "2026-07-04"
+---
+
+# Fred A. Henry
+
+Current Mayor, South Amboy, NJ.
+
+## Sources
+
+- office: Wikidata
+- tenure: Wikidata
+- jurisdiction: Census TIGER 2024
+
+Generated from the Atlas officeholders v3 export (2026-07-04).