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/sac/index.md

@@ -32,7 +32,7 @@ timestamp: "2026-07-03"
 
 # Sac County, IA
 
-County jurisdiction.
+County jurisdiction — 4 officeholders mapped.
 
 ## Demographics (ACS 2023)
 

data/jurisdictions/us/states/ia/counties/sac/municipalities/lake-view/people/john-westergaard.md

@@ -0,0 +1,39 @@
+---
+type: Person
+title: "John Westergaard"
+description: "Mayor, Lake View, IA"
+role: "Mayor, Lake View, IA"
+level: "municipal"
+branch: "executive"
+state: "IA"
+tenure:
+  start: "2026-06-20"
+  current: true
+ids:
+  person: "83639aa6-2cb5-452f-8231-255cb660d10d"
+  office: "01944129-e007-4f60-a673-2e9df76a5c89"
+  tenure: "9fd10de2-d0fd-417d-b0df-5835bd147a39"
+  jurisdiction: "99ab5fe1-f29c-4d63-88df-0f312fff4f64"
+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"
+---
+
+# John Westergaard
+
+Current Mayor, Lake View, 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/sac/municipalities/sac-city/people/scott-bundt.md

@@ -0,0 +1,39 @@
+---
+type: Person
+title: "Scott Bundt"
+description: "Mayor, Sac City, IA"
+role: "Mayor, Sac City, IA"
+level: "municipal"
+branch: "executive"
+state: "IA"
+tenure:
+  start: "2026-06-20"
+  current: true
+ids:
+  person: "fd4fe7d0-df1f-407d-973a-ab4246a13361"
+  office: "79d45d9d-3e4b-4b0a-a93a-3f59b6160f47"
+  tenure: "3b095c19-0b71-4cd9-a63c-3933c641591c"
+  jurisdiction: "220f1ab2-a461-4a78-a8ee-e6d44de4f2d2"
+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"
+---
+
+# Scott Bundt
+
+Current Mayor, Sac City, 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/sac/municipalities/schaller/people/sean-ehrp.md

@@ -0,0 +1,39 @@
+---
+type: Person
+title: "Sean Ehrp"
+description: "Mayor, Schaller, IA"
+role: "Mayor, Schaller, IA"
+level: "municipal"
+branch: "executive"
+state: "IA"
+tenure:
+  start: "2026-06-20"
+  current: true
+ids:
+  person: "3f13567b-d325-4652-9b87-39f0a9e5835f"
+  office: "bfdb3d0f-3fa0-4713-9122-cea294f3464b"
+  tenure: "c7d1fc94-a5a3-49ab-b23b-bcebc6579a8f"
+  jurisdiction: "7a5ee636-dfe7-44d0-82c0-2e85f04cb8dc"
+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"
+---
+
+# Sean Ehrp
+
+Current Mayor, Schaller, 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/sac/municipalities/wall-lake/people/jamie-rohlf.md

@@ -0,0 +1,39 @@
+---
+type: Person
+title: "Jamie Rohlf"
+description: "Mayor, Wall Lake, IA"
+role: "Mayor, Wall Lake, IA"
+level: "municipal"
+branch: "executive"
+state: "IA"
+tenure:
+  start: "2026-06-20"
+  current: true
+ids:
+  person: "e1ac6680-50e2-43ba-9060-284e4e32cfe9"
+  office: "cdd5f26e-7eaa-4537-9094-13bda704fb6d"
+  tenure: "cf99736f-c238-4282-b279-4593080b0282"
+  jurisdiction: "dd9c8ee2-1170-4af9-a135-ba9c3afdc951"
+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"
+---
+
+# Jamie Rohlf
+
+Current Mayor, Wall Lake, IA.
+
+## Sources
+
+- office: Wikidata
+- tenure: Wikidata
+- jurisdiction: Census TIGER 2024
+
+Generated from the Atlas officeholders v3 export (2026-07-04).