## Release v0.51.243 — Release HK (stage-q15)
UX-approved direction via Telegram (workspace feature you named). Backend security hardened through 3 Codex rounds.
### Added
| PR | Author | Feature |
|----|--------|---------|
| #3402 / #3422 | @pamnard | **Drag a file or folder in the workspace tree onto another folder row (or breadcrumb segment) to move it** within the workspace. New `POST /api/file/move`. Drop handlers use `stopPropagation` so the composer `@path` drag (#1097) and OS-file upload-drop (#3411) are unchanged. |
### Verified
- Live end-to-end: `notes.txt` → `docs/` confirmed on disk; legit moves return the correct `new_path`.
- 13 tests (incl. folder-into-self/descendant guard, existing-target collision, and 3 security regressions).
### Security hardening absorbed (3 Codex rounds — all fixed + regression-tested)
1. **TOCTOU symlink race on destination**: a path-based `source.rename(dest)` could be raced by swapping `dest_dir` to an external symlink between validation and rename. Now opens both parent dirs via the workspace-anchored `open_anchored_fd` (openat + `O_NOFOLLOW`, same helper as the upload hardening) and uses `os.rename(leaf, leaf, src_dir_fd=…, dst_dir_fd=…)` with an fd-based collision check; path-based fallback only where `dir_fd` is unsupported.
2. **Symlinked workspace root** returned a confusing 400 after a successful move — returned `new_path` now computed against `ws_root.resolve()`.
3. **Symlinked source entry**: `safe_resolve` follows the final symlink, so moving `link.txt` would move its *target* and dangle the link — now rejected via no-follow `lstat` on the lexical path.
### Gate
- Full pytest suite: **7530 passed, 9 skipped, 3 xpassed, 0 failed**
- ESLint: CLEAN · ruff: CLEAN · browser-smoke: CLEAN
- Codex (regression): SHIP-ONLY-WITH-FIXES ×3 → all applied + tested → **SAFE TO SHIP**
Co-authored-by: pamnard <pamnard@users.noreply.github.com>
