Fix project detail 500 error and round deletion data integrity

- Add missing migration for FileRequirement table and ProjectFile.requirementId
  column (existed in Prisma schema but had no migration, causing all queries
  with `include: { files: true }` to fail with column not found)
- Make projectTags query resilient with try-catch in project.get
- Reset project status to SUBMITTED when round is deleted (prevents orphaned
  ASSIGNED status after ON DELETE SET NULL nullifies roundId)
- Fix round creation/update to allow requiredReviews=0 for filtering rounds
- Parse Zod validation errors in round creation error display

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/server/routers/round.ts

@@ -111,7 +111,7 @@ export const roundRouter = router({
         programId: z.string(),
         name: z.string().min(1).max(255),
         roundType: z.enum(['FILTERING', 'EVALUATION', 'LIVE_EVENT']).default('EVALUATION'),
-        requiredReviews: z.number().int().min(1).max(10).default(3),
+        requiredReviews: z.number().int().min(0).max(10).default(3),
         minAssignmentsPerJuror: z.number().int().min(1).max(50).default(5),
         maxAssignmentsPerJuror: z.number().int().min(1).max(100).default(20),
         sortOrder: z.number().int().optional(),
@@ -208,7 +208,7 @@ export const roundRouter = router({
         name: z.string().min(1).max(255).optional(),
         slug: z.string().min(1).max(100).regex(/^[a-z0-9-]+$/).optional().nullable(),
         roundType: z.enum(['FILTERING', 'EVALUATION', 'LIVE_EVENT']).optional(),
-        requiredReviews: z.number().int().min(1).max(10).optional(),
+        requiredReviews: z.number().int().min(0).max(10).optional(),
         minAssignmentsPerJuror: z.number().int().min(1).max(50).optional(),
         maxAssignmentsPerJuror: z.number().int().min(1).max(100).optional(),
         submissionDeadline: z.date().optional().nullable(),
@@ -615,6 +615,12 @@ export const roundRouter = router({
           userAgent: ctx.userAgent,
         })
 
+        // Reset status for projects that will lose their roundId (ON DELETE SET NULL)
+        await tx.project.updateMany({
+          where: { roundId: input.id },
+          data: { status: 'SUBMITTED' },
+        })
+
         // Delete evaluations first to avoid FK constraint on Evaluation.formId
         // (formId FK may not have CASCADE in older DB schemas)
         await tx.evaluation.deleteMany({