Expand docs/security-architecture.md:
- Add a table-of-contents and an explicit "Trust model" section
framing the security boundary as network-bind + auth (not a
sandbox around --dangerously-skip-permissions), with an
actor/granted matrix and out-of-scope notes.
- Clarify the file-serving hardening: the octet-stream + attachment
+ nosniff combination (not the CSP, which allows 'unsafe-inline')
is what blocks SVG/HTML execution.
- Detail the actual transport security headers: enumerated CSP
widenings (cdn.jsdelivr.net, deepgram wss, data:/blob: img-src,
gesture wasm opt-in), HSTS, X-Frame-Options, localhost-only CORS.
- Add a "Key source files" table and a dated maintenance note.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>