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/ia/counties/crawford/index.md

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

data/jurisdictions/us/states/ia/counties/crawford/municipalities/denison/people/pam-soseman.md

@@ -0,0 +1,39 @@
+---
+type: Person
+title: "Pam Soseman"
+description: "Mayor, Denison, IA"
+role: "Mayor, Denison, IA"
+level: "municipal"
+branch: "executive"
+state: "IA"
+tenure:
+  start: "2019-11-01"
+  current: true
+ids:
+  person: "75958487-a4af-4612-bd59-3ea8e1ed0275"
+  office: "3e7dc98c-f4af-4f4e-9ceb-67f1011666a2"
+  tenure: "20404c84-ee96-45f1-8cd3-e1904674b8a1"
+  jurisdiction: "bfe57fb8-f5f4-4730-90e0-16bd517999c9"
+sources:
+  - field: office
+    source: "Wikidata"
+  - field: tenure
+    source: "Wikidata"
+  - field: jurisdiction
+    source: "Census TIGER 2024"
+confidence: official
+tags: [officeholder, municipal, executive, ia]
+timestamp: "2026-07-04"
+---
+
+# Pam Soseman
+
+Current Mayor, Denison, IA.
+
+## Sources
+
+- office: Wikidata
+- tenure: Wikidata
+- jurisdiction: Census TIGER 2024
+
+Generated from the Atlas officeholders v3 export (2026-07-04).

data/jurisdictions/us/states/ia/counties/crawford/municipalities/schleswig/people/beth-winquist.md

@@ -0,0 +1,39 @@
+---
+type: Person
+title: "Beth Winquist"
+description: "Mayor, Schleswig, IA"
+role: "Mayor, Schleswig, IA"
+level: "municipal"
+branch: "executive"
+state: "IA"
+tenure:
+  start: "2026-06-20"
+  current: true
+ids:
+  person: "b542f2a3-7a7d-4ffb-8583-2e5f4f9a45a2"
+  office: "1e3539bc-5e30-47eb-843b-a3961f91fbfa"
+  tenure: "8339b34c-f0ea-4c0b-b96f-d3512ce3133d"
+  jurisdiction: "64d14bc0-c14e-4f98-969c-60037ffedf7a"
+sources:
+  - field: office
+    source: "Wikidata"
+  - field: tenure
+    source: "Wikidata"
+  - field: jurisdiction
+    source: "Census TIGER 2024"
+confidence: official
+tags: [officeholder, municipal, executive, ia]
+timestamp: "2026-07-04"
+---
+
+# Beth Winquist
+
+Current Mayor, Schleswig, IA.
+
+## Sources
+
+- office: Wikidata
+- tenure: Wikidata
+- jurisdiction: Census TIGER 2024
+
+Generated from the Atlas officeholders v3 export (2026-07-04).