v0.8.68: persist stateful terminal identity and restart limitations safely

[Hmbown]

Problem

Stateful terminal sessions preserve shell state for the lifetime of the current Codewhale process, but the persisted contract is not yet honest or safe across a Codewhale restart. A restarted client must not mistake a reused PID or stale local record for a live shell.

Evidence

The current terminal-session implementation keeps process-local identity, working-directory state, sentinel parsing, cancellation, reset, and approval gating. What is missing is a durable summary and an explicit stale/lost state after restart.

Expected behavior

• Persist a workspace-scoped terminal identity and a useful last-known cwd/environment summary.
• Record enough host/process/session fingerprinting to reject PID reuse.
• After restart, represent an unavailable prior shell as stale/lost rather than silently claiming it was reattached.
• Offer a clear recovery path that starts a new shell without erasing the historical summary.
• Keep reset, cancellation, and approval behavior consistent with live sessions.

Likely files

• crates/tui/src/tools/terminal_session.rs
• crates/tui/src/session_manager.rs
• focused terminal-session persistence tests

Acceptance criteria

• Terminal identity and last-known cwd are saved per workspace.
• Restart cannot reattach based on PID alone.
• Stale/lost sessions are surfaced distinctly from running, canceled, and failed sessions.
• Starting a replacement session preserves an honest historical summary.
• Tests cover normal persistence, process restart, PID-reuse rejection, reset, and cancel.

[Hmbown]

Resolved by #4361 at merge commit 9bfa466. The release now persists terminal identity, last cwd, runtime nonce, stale/lost/replaced state, and replacement history with regression coverage. Full hosted macOS and Windows suites, local TUI tests, and the merged dogfood build are green.