Add elections + demographics layer: candidates and jurisdictions

Two new entity types, built deterministically from the raw exports:

  Candidate (2,494)     — 2026 federal candidates as files under
                          us/states/<st>/candidates/, with office,
                          district, party, incumbent/challenger stance,
                          campaign committee, FEC id.

  Jurisdiction (3,494)  — demographic nodes carrying ACS 2023 data:
                          3,131 counties (deduped from 3,231 mixed-format
                          fips keys) + 363 congressional districts.

This completes the county skeleton nationwide: every US county is now a
browsable node with population, income, poverty, race, education and
housing — even where no officeholders are mapped yet. In Florida the
county index.md merges into the existing dir and reports its officeholder
count alongside demographics (St. Lucie: 33 officeholders + ACS profile).

build.py now reads seven raw inputs in one deterministic pass
(byte-identical on rerun). The mirror now answers: who holds power, who
runs this institution, who is running, and what each place is made of.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

data/jurisdictions/us/states/co/districts/01.md

@@ -0,0 +1,59 @@
+---
+type: Jurisdiction
+title: "CO-01"
+classification: congressional-district
+state: "CO"
+district: "CO-01"
+demographics:
+  population: 735987
+  population_under_18: 142475
+  population_18_64: 347639
+  population_65_plus: 245873
+  median_household_income: 93102
+  poverty_rate: 11.96
+  homeownership_rate: 47.66
+  unemployment_rate: 4.26
+  median_home_value: 637200
+  gini_index: 0.493
+  vacancy_rate: 5.99
+  race_white: 422622
+  race_black: 69897
+  race_asian: 28013
+  hispanic: 208287
+  bachelors_plus: 322177
+sources:
+  - field: demographics
+    source: Census ACS 2023
+confidence: official
+tags: [jurisdiction, congressional-district, co]
+timestamp: "2026-07-03"
+---
+
+# CO-01
+
+Congressional district CO-01.
+
+## Demographics (ACS 2023)
+
+| Measure | Value |
+| --- | --- |
+| Population | 735987 |
+| Under 18 | 142475 |
+| 18–64 | 347639 |
+| 65+ | 245873 |
+| Median household income | 93102 |
+| Poverty rate | 11.96 |
+| Homeownership rate | 47.66 |
+| Unemployment rate | 4.26 |
+| Median home value | 637200 |
+| Gini index | 0.493 |
+| Vacancy rate | 5.99 |
+| White | 422622 |
+| Black | 69897 |
+| Asian | 28013 |
+| Hispanic/Latino | 208287 |
+| Bachelor's or higher | 322177 |
+
+## Source
+
+- demographics: Census ACS 2023

data/jurisdictions/us/states/co/districts/02.md

@@ -0,0 +1,59 @@
+---
+type: Jurisdiction
+title: "CO-02"
+classification: congressional-district
+state: "CO"
+district: "CO-02"
+demographics:
+  population: 728333
+  population_under_18: 156499
+  population_18_64: 274422
+  population_65_plus: 297412
+  median_household_income: 100659
+  poverty_rate: 11.04
+  homeownership_rate: 63.75
+  unemployment_rate: 4.05
+  median_home_value: 721500
+  gini_index: 0.478
+  vacancy_rate: 14.95
+  race_white: 580258
+  race_black: 7906
+  race_asian: 23651
+  hispanic: 102686
+  bachelors_plus: 320529
+sources:
+  - field: demographics
+    source: Census ACS 2023
+confidence: official
+tags: [jurisdiction, congressional-district, co]
+timestamp: "2026-07-03"
+---
+
+# CO-02
+
+Congressional district CO-02.
+
+## Demographics (ACS 2023)
+
+| Measure | Value |
+| --- | --- |
+| Population | 728333 |
+| Under 18 | 156499 |
+| 18–64 | 274422 |
+| 65+ | 297412 |
+| Median household income | 100659 |
+| Poverty rate | 11.04 |
+| Homeownership rate | 63.75 |
+| Unemployment rate | 4.05 |
+| Median home value | 721500 |
+| Gini index | 0.478 |
+| Vacancy rate | 14.95 |
+| White | 580258 |
+| Black | 7906 |
+| Asian | 23651 |
+| Hispanic/Latino | 102686 |
+| Bachelor's or higher | 320529 |
+
+## Source
+
+- demographics: Census ACS 2023