Sync: officeholders v3 — fresh export from live Atlas DB (13,329 tenures)

Re-exported directly from Postgres (10.0.0.116), not Atlas's introspection,
which under-reported the roster (its v3 export had 11,473, missing the
restored Florida League of Cities municipal set). Live DB current tenures:
state 7,561 · municipal 4,009 · county 1,217 · federal 542.

- build.py now reads officeholders-v3.jsonl (was v2); dataset vintage 2026-07-04
- fixed one corrupt start_date at source-export (21021-12-03 -> 2021-12-03,
  Lorraine Borowski, Mayor of Decorah IA)
- scripts/build_viz.py: committed, deterministic generator for the Board's
  county_data.json / county_detail.json (previously built ad-hoc)
- generate_changelog.py: ignore files whose only change is the vintage stamp,
  so the diff reflects government change, not re-export bookkeeping

Person files 11,285 -> 13,329. Non-FL municipal officials (1,903) are in the
tree but not yet county-mappable (place->county crosswalk still NULL).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

data/jurisdictions/us/people/vacant-9cf5c3a3.md

@@ -0,0 +1,42 @@
+---
+type: Person
+title: "Vacant"
+description: "U.S. House of Representatives - GA-13 — Congressional District 13"
+role: "U.S. House of Representatives - GA-13"
+level: "federal"
+branch: "legislative"
+state: "GA"
+district: "Congressional District 13"
+tenure:
+  start: "2025-01-03"
+  current: true
+  notes: "Vacant since David Scott (D) died in office"
+election:
+  next: 2026
+  term_length: 2
+  term_limit: "none"
+ids:
+  person: "9cf5c3a3-0b0d-419d-ac80-e1d588f7701d"
+  office: "4371100f-e67a-4170-b0a4-889bbaeda9c8"
+  tenure: "5497a6bb-e92f-4f27-8c4a-c9541945bca9"
+  jurisdiction: "8709a272-db98-487c-9a4a-0b05f83696d2"
+sources:
+  - field: tenure
+    source: "House Clerk XML 2026-06-10"
+  - field: jurisdiction
+    source: "Census 119th CD 500k"
+confidence: official
+tags: [officeholder, federal, legislative, ga]
+timestamp: "2026-07-04"
+---
+
+# Vacant
+
+Current U.S. House of Representatives - GA-13 (Congressional District 13).
+
+## Sources
+
+- tenure: House Clerk XML 2026-06-10
+- jurisdiction: Census 119th CD 500k
+
+Generated from the Atlas officeholders v3 export (2026-07-04).