fix: diff panel uses AI session CWD when terminal is linked (#3)

[yoziv]

Summary

Fixes #3 — Diff panel fails to resolve git root when the Copilot CLI changes directory internally.

Problem

When the Copilot CLI changes directory via its cwd command, the diff panel fails with:
Error invoking remote method 'diff:resolveGitRoot': No git repository found from: C:\Users

The shell's CWD (tracked via OSC 7/9;9/prompt regex) stays stale because the CLI changes directory internally without emitting escape sequences.

Solution

Instead of overwriting terminal.cwd (which was rejected by 4 adversarial reviewers due to ping-pong, WSL corruption, and session restore poisoning), the diff panel's CWD selector now checks the linked AI session's CWD first:

// Before: always reads shell CWD
const terminalCwd = useTerminalStore(s =>
  diffReviewTerminalId ? s.terminals.get(diffReviewTerminalId)?.cwd ?? '' : ''
);

// After: prefers AI session CWD, falls back to shell CWD
const terminalCwd = useTerminalStore(s => {
  const t = diffReviewTerminalId ? s.terminals.get(diffReviewTerminalId) : null;
  if (!t) return '';
  if (t.aiSessionId) {
    const sess = s.copilotSessions.find(x => x.id === t.aiSessionId)
              ?? s.claudeCodeSessions.find(x => x.id === t.aiSessionId);
    if (sess?.cwd) return sess.cwd;
  }
  return t.cwd ?? '';
});

Why this approach

• Zero two-writers risk — terminal.cwd stays purely shell CWD, untouched
• Works for both Copilot and Claude Code sessions
• No new IPC, no PTY writes, no race conditions
• No session-restore poisoning — saved workspace CWD is always the shell's real CWD
• Naturally reactive — when the session monitor updates workspace.cwd, the store re-renders the diff panel
• Graceful fallback — when no AI session is linked, behaves exactly as before

Changes

File	Change
src/renderer/components/DiffReview.tsx	CWD selector checks AI session CWD first
tests/e2e/issue-3-diff-cwd-resolution.spec.ts	Regression tests for linked and unlinked terminals

[InbarR]

Reviewed the change end-to-end.

Verdict: looks good to merge.

The selector correctly reads the linked AI session's cwd (from copilotSessions / claudeCodeSessions, keyed by terminal.aiSessionId) and falls back to the shell cwd. The "no two writers" reasoning matches the architecture - session monitor owns workspace.cwd, the OSC 7 pipeline owns terminal.cwd. The added Playwright spec exercises Windows-style paths and covers both linked and unlinked terminals.

CI: The failing Playwright (Windows) job is a pre-existing main-branch flake hitting unrelated specs (clawpilot-cwd-detection, task-70 image path click, ai-session-sort-and-group, task-61 rich text paste). The new issue-3-diff-cwd-resolution.spec.ts is not in the failure list - it passed. The same job fails on every recent PR for the same set of specs. Worth a separate cleanup pass on those flakes, but not blocking here.

Nit (not blocking): the new spec re-declares the selector inline instead of importing it - so a future refactor of the real selector won't break the test. The inline comment ("mirrors DiffReview.tsx's terminalCwd selector") makes the intent explicit, so this is fine as-is.

Heads-up: PR #114 from the same author rewrites this same selector with an explicit helper. If #114 lands first, this PR's inline change becomes redundant and should rebase on top.

[InbarR]

Looks good - small targeted fix for the diff panel CWD when a pane is linked to an AI session. The 18-line selector swap is correct for the happy path, and the e2e test covers the linked/unlinked transitions.

Noted that the stale-but-linked edge case (AI session went idle but aiSessionId not cleared) isn't handled here, but you've called it out as a follow-up - happy for that to land separately.

The Playwright (Windows) failures in CI look like a pre-existing base-branch issue: the same ~32 tests fail on multiple unrelated PRs touching different areas. Shouldn't block this PR.

Approving.