Review must-fix: LICENSE, dangling ref, obsolete markers

- LICENSE (MIT, own work) + README license section
- FINDINGS.md per-version notes point into docs/firmware/
- checksum brute-forcers marked superseded (code + tool docs)

README.md

@@ -60,3 +60,8 @@ watch `SYSTEM UPDATE` on the OLED. Keep a stock SD for revert.
 - **No vendor binaries or flash dumps are shipped in this repo** (Sonicware IP).
   Bring your own `.bin` from an official update ZIP; distribute mods as scripts,
   never as full images.
+
+## License
+
+MIT — see `LICENSE`. Covers the code, docs, and photos in this repo (own work
+only); no vendor binaries are shipped.