V4: add WAITING_FOR_FILE_REVIEWER claim status; fix select-outer-parts for split flow

- Add ClaimCaseStatus.WAITING_FOR_FILE_REVIEWER (V4 split flow only)
- Set claim status to WAITING_FOR_FILE_REVIEWER when FileMaker uploads
  the last required document (v3InPersonFlow path), replacing the old
  behaviour that incorrectly auto-advanced to SELECT_OUTER_PARTS
- advanceV3ClaimToOuterPartsIfReady: also allow canAdvance when
  claimCase.status === WAITING_FOR_FILE_REVIEWER so the FileReviewer
  can call select-outer-parts after submitting accident fields
- Add WAITING_FOR_FILE_REVIEWER to CLAIM_USER_PHASE (unified-file-status)
  so the file still resolves to IN_PROGRESS in the unified status report
- Add WAITING_FOR_FILE_REVIEWER to CLAIM_IN_PROGRESS_STATUSES
  (expert-panel-status-report) for the expert report bucket
- Add WAITING_FOR_FILE_REVIEWER to claimInHandling set
  (expert-insurer.service) so insurer stats count these correctly

src/helpers/unified-file-status.ts

@@ -31,6 +31,8 @@ const CLAIM_USER_PHASE = new Set<string>([
   ClaimCaseStatus.SELECTING_OTHER_PARTS,
   ClaimCaseStatus.UPLOADING_REQUIRED_DOCUMENTS,
   ClaimCaseStatus.CAPTURING_PART_DAMAGES,
+  // V4 split flow: FileMaker sealed the file; FileReviewer hasn't picked it up yet.
+  ClaimCaseStatus.WAITING_FOR_FILE_REVIEWER,
 ]);
 
 const INSURER_REVIEW_CLAIM_STATUSES = new Set<string>([