Add selected dashcam imports

Co-authored-by: Copilot <[email protected]>

PLAN.md

@@ -855,6 +855,18 @@ Phase 15 shared list component:
   to the original 87-file count and byte total, left every real video untouched, unmounted
   `/mnt/dashcam`, and kept the service active. Bulk delete uses the same validated per-file removal
   path but was not run against the real card because it would intentionally erase all footage.
+- **Selected import enhancement and real-hardware verification (2026-08-09)**: added per-row
+  Import buttons, checkboxes, Select all/Clear selection, and Import selected so importing is no
+  longer all-or-nothing. The backend validates every selected path with the same mount-boundary
+  protections as deletion, de-duplicates selections, preserves relative folders, tolerates a
+  stale/missing file while importing the remaining valid selection, and keeps the existing
+  same-size skip behavior. Before committing, paused background dashcam uploads, created a
+  disposable `YARIS_OBD_IMPORT_TEST.MP4` on the physical card, selected it in the real mobile-width
+  UI, and confirmed exactly one file copied with identical contents. A row-level repeat correctly
+  skipped the existing copy; Select all selected all 88 visible rows and Clear selection reset the
+  action. Removed both disposable copies, restored uploads, and verified the card returned to its
+  original 87 files/29,615,111,758 bytes unmounted. The refined UI was then re-tested against a
+  real existing video: it reported one skip, cleared the checkbox, and re-enabled all controls.
 
 ### Phase 17: Local imported-video browser + player — 🚧 PLANNED
 Same file-browser treatment for videos already imported to the Pi's own disk