Fix Claude CLI pane completion status

[danshapiro]

Summary

• Repair the watcher-race test readiness barrier by waiting for the retained ownership stamp.
• Return Claude Stop-hook completion through Claude's terminalSequence response so the terminal activity tracker can observe it.
• Make Windows hook commands safe for Git Bash and PowerShell, and resolve Claude transcript roots from USERPROFILE with path-equivalent deduplication.
• Add execution-level hook/profile coverage and Windows workflow steps.

Verification

• Focused platform, activity, transcript, and WebSocket tests passed.
• pnpm run test passed, including cloud Vitest, source-runtime, Rust workspace, and Electron (395 tests).
• Pre-push formatting, workspace clippy, and affected-crate tests passed.
• Windows Rust test harnesses cross-compiled. Native Windows runtime tests are configured in the Windows workflow but were not run locally.

No live Claude CLI or model was invoked.