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/ma/counties/norfolk/index.md

@@ -32,7 +32,7 @@ timestamp: "2026-07-03"
 
 # Norfolk County, MA
 
-County jurisdiction.
+County jurisdiction — 2 officeholders mapped.
 
 ## Demographics (ACS 2023)
 

data/jurisdictions/us/states/ma/counties/norfolk/municipalities/quincy/people/thomas-p-koch.md

@@ -0,0 +1,39 @@
+---
+type: Person
+title: "Thomas P. Koch"
+description: "Mayor, Quincy, MA"
+role: "Mayor, Quincy, MA"
+level: "municipal"
+branch: "executive"
+state: "MA"
+tenure:
+  start: "2026-06-20"
+  current: true
+ids:
+  person: "2cad880e-9d96-453e-bd33-f0493ee50267"
+  office: "ad101db0-de67-466d-961b-335945a29643"
+  tenure: "b801f5e9-2d82-4cac-bb27-3b780cdb4b2a"
+  jurisdiction: "7accabce-51e2-462d-9cde-3f4ce44342ba"
+sources:
+  - field: office
+    source: "Wikidata"
+  - field: tenure
+    source: "Wikidata"
+  - field: jurisdiction
+    source: "Census TIGER 2024"
+confidence: official
+tags: [officeholder, municipal, executive, ma]
+timestamp: "2026-07-04"
+---
+
+# Thomas P. Koch
+
+Current Mayor, Quincy, MA.
+
+## Sources
+
+- office: Wikidata
+- tenure: Wikidata
+- jurisdiction: Census TIGER 2024
+
+Generated from the Atlas officeholders v3 export (2026-07-04).

data/jurisdictions/us/states/ma/counties/norfolk/municipalities/weymouth-town/people/robert-l-hedlund.md

@@ -0,0 +1,39 @@
+---
+type: Person
+title: "Robert L. Hedlund"
+description: "Mayor, Weymouth, MA — Weymouth Town"
+role: "Mayor, Weymouth, MA"
+level: "municipal"
+branch: "executive"
+state: "MA"
+tenure:
+  start: "2016-01-04"
+  current: true
+ids:
+  person: "76d0fb54-e867-4895-b217-0c46b7eb5df5"
+  office: "914e5e4b-973c-4e2c-96b9-dc9f26b849a6"
+  tenure: "21e96058-5410-4ffe-b59d-18bebc5e04fd"
+  jurisdiction: "e39bfce5-ed90-4fad-a800-65a4799e6fed"
+sources:
+  - field: office
+    source: "Wikidata"
+  - field: tenure
+    source: "Wikidata"
+  - field: jurisdiction
+    source: "Census TIGER 2024"
+confidence: official
+tags: [officeholder, municipal, executive, ma]
+timestamp: "2026-07-04"
+---
+
+# Robert L. Hedlund
+
+Current Mayor, Weymouth, MA (Weymouth Town).
+
+## Sources
+
+- office: Wikidata
+- tenure: Wikidata
+- jurisdiction: Census TIGER 2024
+
+Generated from the Atlas officeholders v3 export (2026-07-04).