feat(labs): draft review, confirm with normalization, discard

- Add ConfirmDraftBody schema to shared types
- Implement GET /api/labs/drafts/:id (retrieves draft with extracted data)
- Implement POST /api/labs/drafts/:id/confirm (normalizes markers, inserts lab draw + biomarkers in transaction, marks draft confirmed)
- Implement POST /api/labs/drafts/:id/discard (marks draft discarded)
- Add comprehensive test suite with 3 new tests

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

shared/src/types.ts

@@ -37,3 +37,10 @@ export const ExtractedDraft = z.object({
   markers: z.array(ExtractedMarker).default([]),
 });
 export type ExtractedDraft = z.infer<typeof ExtractedDraft>;
+
+export const ConfirmDraftBody = z.object({
+  collectedDate: z.string().regex(/^\d{4}-\d{2}-\d{2}$/),
+  labName: z.string().nullable().default(null),
+  markers: z.array(ExtractedMarker).min(1),
+});
+export type ConfirmDraftBody = z.infer<typeof ConfirmDraftBody>;