Add a batch import for multicam datasets

[romleiaj]

A high-level overview of this branch (dev/multicollect-import, off dev/sealtk) for reviewers.

What it does

Imports many multicam datasets in one action. You point DIVE at a top-level folder whose
subfolders are "collects"; each collect holds the same set of camera subfolders (e.g. EO/,
IR/, UV/) of image frames. DIVE scans and validates them, shows a summary table, and then
creates one multicam dataset per collect — referencing the imagery in place (nothing is copied).

rootFolder/
  collect_001/   EO/ IR/ UV/   -> one multicam dataset
  collect_002/   EO/ IR/ UV/   -> one multicam dataset
  ...

Why it exists

Seal (and similar aerial) surveys produce dozens of collects in the same camera layout.
Importing them one at a time through the normal multicam dialog is slow and error-prone. This
adds a single "scan a folder, import them all" flow with up-front validation, so a whole survey
lands in a few clicks and bad collects are flagged instead of silently failing mid-way.

GUI elements added

• "MultiCam Batch" entry in the desktop Import menu (ImportButton).
• Batch Multicam Import dialog (ImportMultiCamBatchDialog.vue):
  • "Choose Root Folder" button + scan progress.
  • A summary table — one row per collect showing its cameras (with per-camera frame
    counts), any validation problems (blocking, red) or warnings (non-blocking, amber,
    e.g. differing frame counts), and a live status chip (Ready / Importing / Imported /
    Failed / Skipped).
  • An "Import N Collects" button and a final "imported X of Y (Z failed / skipped)" summary.

How it's implemented (high level)

• Scanner (multiCollectImport.ts, desktop backend) — lists collect folders, finds the
  image-bearing camera subfolders, derives the canonical camera set (union of camera names
  across collects, matched case-insensitively), validates it (must be 2–3 valid camera names),
  and per collect produces either ready-to-run import arguments or a list of blocking problems.
  It reuses the existing multicam import backend (findImagesInFolder, the subfolder-layout
  helpers, beginMultiCamImport → finalizeImport → convert) so no new import path or copying
  is introduced.
• IPC + API — one new channel (scan-multicam-batch) and its api.ts wrapper; a small set
  of result types (MultiCamBatchScanResult / …Collect / …Camera) in constants.ts.
• Dialog drives the flow: scan → review → import each valid collect sequentially, with a
  per-collect try/catch so one failure doesn't stop the batch (mirrors the existing bulk
  import). Status is tracked reactively and the recents list refreshes after each import.

Files it touches (8 files, ~914 lines)

Area	Key files
Scanner (backend)	client/platform/desktop/backend/native/multiCollectImport.ts (+ 263-line spec)
Desktop wiring	client/platform/desktop/backend/ipcService.ts, frontend/api.ts, constants.ts
Dialog UI	client/platform/desktop/frontend/components/ImportMultiCamBatchDialog.vue
Menu / mount	client/dive-common/components/ImportButton.vue, platform/desktop/frontend/components/Recent.vue

Platform support

Desktop only. The scanner, IPC channel, and dialog all live under platform/desktop. The
shared ImportButton gained a batchMultiCamImport prop that defaults to false, and only
the desktop Recent.vue turns it on — so the menu entry never appears on web and nothing else
changes there. (Batch import needs direct filesystem folder scanning, which the web platform
doesn't do.)

[BryonLewis]

Some updates to this PR:

• Merged the base in so I could check the percentage scaling
• Added support for skipping and renaming datasets that are imported using the batch import
• Added support for the batch import to the Web as well
• Updated the system so the EO is typically on the left while IR is on the right side when imported
• disable stereo service when in multicam mode and subType isn't 'stereo'

Demo Video:

20260708-DIVE-MultiCamBatchImport_small.mp4

[BryonLewis]

I left it as a dropdown under image-sequence and added some functionality to skip certain sub-folders, as well as edit the name of the dataset during import.

Added the same functionality to the web version.

Updated documentation as well.