wave2 phase 6: GPS-jam stretch — investigated, held pending permission

Probed gpsjam.org per SPEC2 §7's investigate-first rule. Findings: the data is
real and clean (https://gpsjam.org/data/<YYYY-MM-DD>-h3_4.csv, columns
hex,count_good_aircraft,count_bad_aircraft, H3 res-4, published ~04:00 UTC for
the prior day). But two blockers: no Access-Control-Allow-Origin (browser can't
fetch directly — would need a serve.py proxy), and ambiguous licensing (no
stated terms; derived from ADS-B Exchange, which is non-commercial and
protective of redistribution). Per spec — ambiguous licensing → document and
stop, don't scrape around an unwilling origin — the layer is NOT built; the full
findings are recorded in the README roadmap so John can decide after getting
permission from John Wiseman / ADS-B Exchange.

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

README.md

@@ -110,7 +110,7 @@ record.py             optional dev daemon: snapshots live aircraft into data/his
 
 - **Live AIS** by default (aisstream.io key) — implemented, opt-in today.
 - **Historical recording** — implemented locally via `record.py` (see *Time-travel* above); a VPS-side recorder for replay in production is a future step.
-- **GPS-jamming heatmap** from [gpsjam.org](https://gpsjam.org) daily H3 tiles.
+- **GPS-jamming heatmap** from [gpsjam.org](https://gpsjam.org) daily H3 tiles — *investigated, held pending permission.* The data is real and clean: `https://gpsjam.org/data/<YYYY-MM-DD>-h3_4.csv` (published ~04:00 UTC for the prior day), columns `hex,count_good_aircraft,count_bad_aircraft` — an H3 resolution-4 index plus counts, easily rendered as translucent red hexes (interference = `bad / (good + bad)`). Two blockers stopped us building it: (1) the endpoint sends **no `Access-Control-Allow-Origin`**, so a browser can't fetch it directly — a `serve.py` proxy would be required; and (2) **licensing is ambiguous** — gpsjam.org publishes no license or reuse terms, and the data is derived from ADS-B Exchange (non-commercial, protective of redistribution). Re-serving it from a public site without an explicit grant would be scraping around an unwilling origin, so this waits on John obtaining permission from John Wiseman / ADS-B Exchange first.
 - **Classified-sat amateur TLEs** (community "classfd" catalogs) for birds Celestrak omits.
 - **Economic side panel** — Brent / WTI oil futures synced to the timeline.
 - **Cesium ion terrain & photorealistic 3D tiles** (needs a token).