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/ca/counties/sacramento/index.md

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

data/jurisdictions/us/states/ca/counties/sacramento/municipalities/elk-grove/people/bobbie-singh-allen.md

@@ -0,0 +1,39 @@
+---
+type: Person
+title: "Bobbie Singh-Allen"
+description: "Mayor, Elk Grove, CA"
+role: "Mayor, Elk Grove, CA"
+level: "municipal"
+branch: "executive"
+state: "CA"
+tenure:
+  start: "2020-11-01"
+  current: true
+ids:
+  person: "7e619997-79ac-4a99-914c-7554a1010291"
+  office: "529e522c-5493-4034-8428-b6fd73a87a13"
+  tenure: "ec6e04b0-5138-4886-819f-2f0abbf8fe13"
+  jurisdiction: "d1a5e876-337f-4ae1-a0a0-8e92054d611f"
+sources:
+  - field: office
+    source: "Wikidata"
+  - field: tenure
+    source: "Wikidata"
+  - field: jurisdiction
+    source: "Census TIGER 2024"
+confidence: official
+tags: [officeholder, municipal, executive, ca]
+timestamp: "2026-07-04"
+---
+
+# Bobbie Singh-Allen
+
+Current Mayor, Elk Grove, CA.
+
+## Sources
+
+- office: Wikidata
+- tenure: Wikidata
+- jurisdiction: Census TIGER 2024
+
+Generated from the Atlas officeholders v3 export (2026-07-04).

data/jurisdictions/us/states/ca/counties/sacramento/municipalities/sacramento/people/darrell-steinberg.md

@@ -0,0 +1,39 @@
+---
+type: Person
+title: "Darrell Steinberg"
+description: "Mayor, Sacramento, CA"
+role: "Mayor, Sacramento, CA"
+level: "municipal"
+branch: "executive"
+state: "CA"
+tenure:
+  start: "2016-12-13"
+  current: true
+ids:
+  person: "6ebf183a-d3d0-47a6-ba5c-4bb8e0d067bf"
+  office: "be396bd5-33fb-400d-b94e-3c883b37745e"
+  tenure: "affac8ab-b022-4720-b545-f08351e352ec"
+  jurisdiction: "945f7f03-0fa0-4da3-8395-6a6b90993de4"
+sources:
+  - field: office
+    source: "Wikidata"
+  - field: tenure
+    source: "Wikidata"
+  - field: jurisdiction
+    source: "Census TIGER 2024"
+confidence: official
+tags: [officeholder, municipal, executive, ca]
+timestamp: "2026-07-04"
+---
+
+# Darrell Steinberg
+
+Current Mayor, Sacramento, CA.
+
+## Sources
+
+- office: Wikidata
+- tenure: Wikidata
+- jurisdiction: Census TIGER 2024
+
+Generated from the Atlas officeholders v3 export (2026-07-04).