Signet 0.3.4

v0.3.4 New: in-app crash reporter. If the app crashes, the next launch offers to file a pre-filled GitHub Issue with the stack trace. Cryptographic material (paired secrets, verify codes, backup payloads, contact labels) is redacted on-device before anything leaves your phone. No in-process network — "File issue" opens your OS browser. Fixed: in-person pairing deadlock (#1). Both devices now wait for both scan + show before advancing to verification.