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/me/counties/androscoggin/index.md

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

data/jurisdictions/us/states/me/counties/androscoggin/municipalities/auburn/people/jeffrey-d-harmon.md

@@ -0,0 +1,39 @@
+---
+type: Person
+title: "Jeffrey D. Harmon"
+description: "Mayor, Auburn, ME"
+role: "Mayor, Auburn, ME"
+level: "municipal"
+branch: "executive"
+state: "ME"
+tenure:
+  start: "2023-12-14"
+  current: true
+ids:
+  person: "74e23bca-4818-4d5a-9cc9-b4d5a34390a0"
+  office: "e0dc52ad-19e7-4e41-924a-7c0dd2a504f3"
+  tenure: "63527b7b-6e8d-4c09-bafb-326dd7501742"
+  jurisdiction: "434e308e-24f3-4e93-9a2a-0f55eb1ddc11"
+sources:
+  - field: office
+    source: "Wikidata"
+  - field: tenure
+    source: "Wikidata"
+  - field: jurisdiction
+    source: "Census TIGER 2024"
+confidence: official
+tags: [officeholder, municipal, executive, me]
+timestamp: "2026-07-04"
+---
+
+# Jeffrey D. Harmon
+
+Current Mayor, Auburn, ME.
+
+## Sources
+
+- office: Wikidata
+- tenure: Wikidata
+- jurisdiction: Census TIGER 2024
+
+Generated from the Atlas officeholders v3 export (2026-07-04).

data/jurisdictions/us/states/me/counties/androscoggin/municipalities/lewiston/people/carl-l-sheline.md

@@ -0,0 +1,39 @@
+---
+type: Person
+title: "Carl L. Sheline"
+description: "Mayor, Lewiston, ME"
+role: "Mayor, Lewiston, ME"
+level: "municipal"
+branch: "executive"
+state: "ME"
+tenure:
+  start: "2026-06-20"
+  current: true
+ids:
+  person: "5e6de762-420c-4a39-a17e-e551bdb7ba1b"
+  office: "1812f252-c352-4c20-b9e4-2a80d333d429"
+  tenure: "e63d1f7e-bfa2-4261-bf05-78167b60edcb"
+  jurisdiction: "5d0a8efd-fc67-46d6-aeb7-ee1dc0753488"
+sources:
+  - field: office
+    source: "Wikidata"
+  - field: tenure
+    source: "Wikidata"
+  - field: jurisdiction
+    source: "Census TIGER 2024"
+confidence: official
+tags: [officeholder, municipal, executive, me]
+timestamp: "2026-07-04"
+---
+
+# Carl L. Sheline
+
+Current Mayor, Lewiston, ME.
+
+## Sources
+
+- office: Wikidata
+- tenure: Wikidata
+- jurisdiction: Census TIGER 2024
+
+Generated from the Atlas officeholders v3 export (2026-07-04).