Wrong TUI leaks into session

Possible technical cause of the “wrong TUI leaks into session” bug:

• PTY/shared terminal sessions not fully isolated
• stdout/stderr streams multiplexed incorrectly
• incorrect reuse of session_id or websocket state
• race conditions during session attach/detach
• cached UI state not reset when switching agent/session
• possible cross-talk between TUI renderer and backend event bus

Things worth checking:

• strict per-PTY isolation
• full cleanup on disconnect
• renderer state invalidation
• strong binding between user/session/terminal
• locking around concurrent streams
• separate namespaces for TUI state

This looks more like a session orchestration issue than an AI model issue itself.