v5.3.6

Changelog

• 497b4df: agent: /model pick survives turns on the already-open channel (#85) (@bownux)
• 62f6c2e: agent: permission modes - /perms confirm | edits | all (Claude-Code-style bypass) (#84) (@bownux)
• bfe5657: release: v5.3.6 prep (permission modes + model pin + audit round 1) (#87) (@bownux)
• 0d28e18: tui: beautification audit round 1 (help pager, masked key, honest badges, one confirm) (#86) (@bownux)