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/nc/counties/davidson/municipalities/midway/people/john-byrum.md

@@ -0,0 +1,39 @@
+---
+type: Person
+title: "John Byrum"
+description: "Mayor, Midway, NC"
+role: "Mayor, Midway, NC"
+level: "municipal"
+branch: "executive"
+state: "NC"
+tenure:
+  start: "2026-06-20"
+  current: true
+ids:
+  person: "4853cd4a-69e1-4f3d-9e72-8391237899a0"
+  office: "af829d6e-935b-4664-b796-c6b139fea69c"
+  tenure: "d3f15e16-77d6-45b4-af30-88275a57df2b"
+  jurisdiction: "ab22db5d-4370-464b-8a4b-5946de991557"
+sources:
+  - field: office
+    source: "Wikidata"
+  - field: tenure
+    source: "Wikidata"
+  - field: jurisdiction
+    source: "Census TIGER 2024"
+confidence: official
+tags: [officeholder, municipal, executive, nc]
+timestamp: "2026-07-04"
+---
+
+# John Byrum
+
+Current Mayor, Midway, NC.
+
+## Sources
+
+- office: Wikidata
+- tenure: Wikidata
+- jurisdiction: Census TIGER 2024
+
+Generated from the Atlas officeholders v3 export (2026-07-04).