feat(settings): editable NAS rclone remote + live test-connection

[Xander-git]

Context

The Settings → NAS Remote section was read-only: it displayed the configured rclone remote name (nas.remote) and base root as static labels and only appeared when nas-mode equipment existed. Changing the remote meant hand-editing config.yaml. This makes the whole rclone connection configurable (and testable) from the GUI.

What changed

• Editable section (src/exlab_wizard/ui/pages/settings.py)
  • Remote: a dropdown of remotes detected via rclone listremotes, with a Refresh button that re-lists using the typed config path. The saved remote stays selectable even when not currently detected.
  • Base root and Config path (rclone --config <path>) inputs.
  • All three two-way-bind the draft nas block.
  • The section is always shown (after Equipment) — settings_sections_for no longer gates on nas-mode equipment; the dead _nas_mode_equipment helper was removed.
• Live Test connection (src/exlab_wizard/ui/mount.py)
  • Probes the typed (unsaved) remote + config path directly through RcloneDriver.about() so a fresh selection can be validated before saving. This is intentionally independent of deps.equipment_probe (which POST /setup/test-equipment still uses against the saved config).
  • Added _list_nas_remotes to back the Refresh affordance.
• Tests + docs: rewrote the NAS-remote settings tests and the mount probe tests; updated tests/e2e/ux_catalog.py and regenerated docs/UX_INTERACTIONS.md.

Note on one non-obvious fix

ui.select rejects a value that isn't None or in its options, but nas.remote is a str ("" when unset) and a None reaching that field fails validation on Save. Resolved with a None ↔ "" conversion at the binding boundary (forward/backward).

Testing

• tests/unit/ui/test_settings_nas_remote.py — 35 passed
• tests/unit/ui/test_mount.py — 182 passed
• rest of tests/unit/ui — 447 passed, 19 skipped
• tests/e2e/test_ux_documentation.py — 4 passed
• uvx ruff check on changed files — clean
• Live GUI click-through not yet performed.

🤖 Generated with Claude Code