- Introduces ClientBridge — the abstract boundary between AgentSession and external clients (ACP, TUI), defining terminal handle and permission request contracts
- Adds ACP permission gating in AgentSession for destructive tools (bash, edit, write, ast_edit): allow-once, reject-once, allow-always with caching
- Wires todo tracking, model cycling/retry-fallback chains, and auto-compaction into the session lifecycle
