Restore Map (FEC overlay), Interactive Charts, and Chapter 5 FEC (#19)

Recovers from two incidents that broke the live site:

1. 9d47afc deleted 1,498 lines from index.html (Jun 26), removing Chapter 5,
   Interactive Charts, Data Sources, and the footer. The page was left as
   broken, unclosed HTML.

2. d769a04 removed the FEC employer circle layer from the county map (Jun 15),
   replacing it with a BAI-only choropleth.

Restoration:
- Rebuilt index.html from last complete version (f305abe, 1,496 lines)
- Restored county unemployment + FEC overlay map section and verbiage
- Restored maps/dmv_counties.html FEC employer contributions layer (05b4d1a)
- Restored Chapter 5 — Who Funds the Freeze
- Restored Interactive Charts (11 Plotly iframes), now visible by default

Author: thedatavigilante