This patch release strengthens SecureBit.chat across verification, sanitization, privacy, transport abuse resistance, cache safety, and repository hygiene.
### Security hardening
- Bound SAS verification to the actual DTLS fingerprint strings of both peers.
- Replaced regex-based chat sanitization with DOMPurify-backed sanitization.
- Made WebRTC privacy mode explicit and kept relay-only state synchronized at runtime.
- Removed production exposure of internal debug/control hooks.
- Added receiver-side rate limiting for inbound chat messages.
- Added receiver-side throttling for inbound file chunks.
### Runtime and privacy safety
- Hardened service-worker caching so only explicitly allowlisted safe assets are cached.
- Removed an untracked disconnect timer so teardown no longer leaves delayed callbacks behind.
- Preserved relay-only TURN behavior while making privacy implications clearer when relay-only mode is disabled or TURN is unavailable.
### Repository hygiene
- Stopped tracking `node_modules` in Git so platform-specific dependency binaries no longer pollute the repository or break cross-platform builds.