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/sd/counties/union/index.md

@@ -32,7 +32,7 @@ timestamp: "2026-07-03"
 
 # Union County, SD
 
-County jurisdiction.
+County jurisdiction — 3 officeholders mapped.
 
 ## Demographics (ACS 2023)
 

data/jurisdictions/us/states/sd/counties/union/municipalities/beresford/people/eli-seeley.md

@@ -0,0 +1,39 @@
+---
+type: Person
+title: "Eli Seeley"
+description: "Mayor, Beresford, SD"
+role: "Mayor, Beresford, SD"
+level: "municipal"
+branch: "executive"
+state: "SD"
+tenure:
+  start: "2026-06-20"
+  current: true
+ids:
+  person: "5fdf3c6d-da5b-41c8-a6ef-862e77fcba2e"
+  office: "20213d8d-05cc-4866-99dc-d7ccbe1afdc1"
+  tenure: "b59cb192-b25e-4f6f-822c-94374086c193"
+  jurisdiction: "9699ce3c-53c0-4f63-ad52-e356e7d2a7b0"
+sources:
+  - field: office
+    source: "Wikidata"
+  - field: tenure
+    source: "Wikidata"
+  - field: jurisdiction
+    source: "Census TIGER 2024"
+confidence: official
+tags: [officeholder, municipal, executive, sd]
+timestamp: "2026-07-04"
+---
+
+# Eli Seeley
+
+Current Mayor, Beresford, SD.
+
+## Sources
+
+- office: Wikidata
+- tenure: Wikidata
+- jurisdiction: Census TIGER 2024
+
+Generated from the Atlas officeholders v3 export (2026-07-04).

data/jurisdictions/us/states/sd/counties/union/municipalities/elk-point/people/deborah-mccreary.md

@@ -0,0 +1,39 @@
+---
+type: Person
+title: "Deborah McCreary"
+description: "Mayor, Elk Point, SD"
+role: "Mayor, Elk Point, SD"
+level: "municipal"
+branch: "executive"
+state: "SD"
+tenure:
+  start: "2026-06-20"
+  current: true
+ids:
+  person: "cebc361e-10dd-4bcf-80ca-cd237db964d7"
+  office: "0a61de1e-2405-42c8-9f93-3f991f6d95a5"
+  tenure: "11dfd569-dd3c-4a21-9f6f-be3885f1410b"
+  jurisdiction: "faaa90f1-ba93-4228-8e60-03501f549087"
+sources:
+  - field: office
+    source: "Wikidata"
+  - field: tenure
+    source: "Wikidata"
+  - field: jurisdiction
+    source: "Census TIGER 2024"
+confidence: official
+tags: [officeholder, municipal, executive, sd]
+timestamp: "2026-07-04"
+---
+
+# Deborah McCreary
+
+Current Mayor, Elk Point, SD.
+
+## Sources
+
+- office: Wikidata
+- tenure: Wikidata
+- jurisdiction: Census TIGER 2024
+
+Generated from the Atlas officeholders v3 export (2026-07-04).

data/jurisdictions/us/states/sd/counties/union/municipalities/north-sioux-city/people/patricia-teel.md

@@ -0,0 +1,39 @@
+---
+type: Person
+title: "Patricia Teel"
+description: "Mayor, North Sioux City, SD"
+role: "Mayor, North Sioux City, SD"
+level: "municipal"
+branch: "executive"
+state: "SD"
+tenure:
+  start: "2023-01-01"
+  current: true
+ids:
+  person: "28702380-2150-4de4-8999-c674c7895f3e"
+  office: "41c4cdf3-df06-46e4-ad74-a5e532ed1f5c"
+  tenure: "23d8ec44-ec89-4f04-9efb-6908b0249b49"
+  jurisdiction: "52e0e530-8901-46f3-8847-1e72aba89dc8"
+sources:
+  - field: office
+    source: "Wikidata"
+  - field: tenure
+    source: "Wikidata"
+  - field: jurisdiction
+    source: "Census TIGER 2024"
+confidence: official
+tags: [officeholder, municipal, executive, sd]
+timestamp: "2026-07-04"
+---
+
+# Patricia Teel
+
+Current Mayor, North Sioux City, SD.
+
+## Sources
+
+- office: Wikidata
+- tenure: Wikidata
+- jurisdiction: Census TIGER 2024
+
+Generated from the Atlas officeholders v3 export (2026-07-04).