fix(review): contain untracked reads honestly

[ahmedragab20]

Summary

Follow-up after #8 and the native-file hardening slice. Untracked diffs and EditorConfig no longer walk the repo through Node fs. Denied, missing, or unavailable untracked files are omitted; the tracked patch is kept; /api/diff, inspect, MCP get_diff, and the web UI report complete: false instead of a full snapshot.

Also stops the browser UI from importing the Node GitHub client, and fails the Vite build if a Node builtin leaks into the client bundle.

What landed

• Untracked file contents and EditorConfig are read through the native capability helper; Git path lists are NUL-delimited.
• Helper-unavailable / denied symlink / listing failures keep the tracked diff and set complete / omittedPaths.
• Tracked async git diff failures propagate instead of becoming an empty successful review.
• getFileContent / resolveFileVersion honor staged, revision-range, and show-mode blob specs.
• Inspect cache fingerprints include completeness, not just the patch.
• Web banner when a review is incomplete.
• classifyPrComments moved to src/lib/pr-comments.ts; Vite browserOnlyPlugin rejects Node builtins in the client bundle.

Verification

• pnpm exec vitest run (targeted containment files): 6 files, 227 tests passed.
• pnpm test:ts: 178 files, 1,849 tests passed.
• pnpm exec vite build: passed (existing >500 kB chunk warning).

I did not re-run the waived #8 manual browser/latency matrix, and there is no browser MCP in this session to click the new incomplete banner. Data path is covered by useDiff / /api/diff tests.

Still deferred

This is not the rest of the hardening roadmap. Still open, in order:

1. Git stage/revert, editor launch, search/fff, remaining Rust callers, OS matrix (A02 remainder).
2. Full snapshot-correct previews and guarded mutations (A03/A04).
3. Durable isolated review state (A08–A13).
4. Headless contract, publishing/egress, typecheck/CI/perf (A14+).
5. #8 waived items: cross-browser / edit-mode / navigation matrix, before/after latency, human verification of the original scroll/comment workflows.

No release.