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/santa-barbara/index.md

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

data/jurisdictions/us/states/ca/counties/santa-barbara/municipalities/guadalupe/people/ariston-julian.md

@@ -0,0 +1,39 @@
+---
+type: Person
+title: "Ariston Julian"
+description: "Mayor, Guadalupe, CA"
+role: "Mayor, Guadalupe, CA"
+level: "municipal"
+branch: "executive"
+state: "CA"
+tenure:
+  start: "2026-06-20"
+  current: true
+ids:
+  person: "141f703f-4730-4132-a1ee-925ccdaea747"
+  office: "4f02ab9e-7662-41b6-ba6a-91a73ddcd2cf"
+  tenure: "ba5b194c-0c8b-4f9e-9761-f0b6d92bb7b5"
+  jurisdiction: "a37bd6ac-c556-4205-a97c-4a3ee2753708"
+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"
+---
+
+# Ariston Julian
+
+Current Mayor, Guadalupe, 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/santa-barbara/municipalities/santa-barbara/people/cathy-murillo.md

@@ -0,0 +1,39 @@
+---
+type: Person
+title: "Cathy Murillo"
+description: "Mayor, Santa Barbara, CA"
+role: "Mayor, Santa Barbara, CA"
+level: "municipal"
+branch: "executive"
+state: "CA"
+tenure:
+  start: "2018-01-09"
+  current: true
+ids:
+  person: "a8cc12ff-e588-4485-8013-8fc02ee21cc4"
+  office: "b4607af6-f706-4604-88f2-2ed5532c47c3"
+  tenure: "bf1a86d7-e228-43fb-8ba4-ad96675b08f5"
+  jurisdiction: "14d46ac5-21de-4ca1-b121-b35441544c2a"
+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"
+---
+
+# Cathy Murillo
+
+Current Mayor, Santa Barbara, CA.
+
+## Sources
+
+- office: Wikidata
+- tenure: Wikidata
+- jurisdiction: Census TIGER 2024
+
+Generated from the Atlas officeholders v3 export (2026-07-04).