Decouple projects from rounds with RoundProject join table

Projects now exist at the program level instead of being locked to a
single round. A new RoundProject join table enables many-to-many
relationships with per-round status tracking. Rounds have sortOrder
for configurable progression paths.

- Add RoundProject model, programId on Project, sortOrder on Round
- Migration preserves existing data (roundId -> RoundProject entries)
- Update all routers to query through RoundProject join
- Add assign/remove/advance/reorder round endpoints
- Add Assign, Advance, Remove Projects dialogs on round detail page
- Add round reorder controls (up/down arrows) on rounds list
- Show all rounds on project detail page

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

prisma/migrations/20260202120000_decouple_projects_from_rounds/migration.sql

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+-- Step 1: Add sortOrder to Round
+ALTER TABLE "Round" ADD COLUMN "sortOrder" INTEGER NOT NULL DEFAULT 0;
+
+-- Set initial sort order by creation date within each program
+UPDATE "Round" r SET "sortOrder" = sub.rn - 1
+FROM (
+  SELECT id, ROW_NUMBER() OVER (PARTITION BY "programId" ORDER BY "createdAt") as rn
+  FROM "Round"
+) sub
+WHERE r.id = sub.id;
+
+-- Step 2: Add programId to Project (nullable initially)
+ALTER TABLE "Project" ADD COLUMN "programId" TEXT;
+
+-- Populate programId from the round's program
+UPDATE "Project" p SET "programId" = r."programId"
+FROM "Round" r WHERE p."roundId" = r."id";
+
+-- Make programId required
+ALTER TABLE "Project" ALTER COLUMN "programId" SET NOT NULL;
+
+-- Add foreign key constraint
+ALTER TABLE "Project" ADD CONSTRAINT "Project_programId_fkey"
+  FOREIGN KEY ("programId") REFERENCES "Program"("id") ON DELETE CASCADE ON UPDATE CASCADE;
+
+-- Step 3: Create RoundProject table
+CREATE TABLE "RoundProject" (
+    "id" TEXT NOT NULL,
+    "roundId" TEXT NOT NULL,
+    "projectId" TEXT NOT NULL,
+    "status" "ProjectStatus" NOT NULL DEFAULT 'SUBMITTED',
+    "addedAt" TIMESTAMP(3) NOT NULL DEFAULT CURRENT_TIMESTAMP,
+
+    CONSTRAINT "RoundProject_pkey" PRIMARY KEY ("id")
+);
+
+-- Populate RoundProject from existing Project.roundId and status
+INSERT INTO "RoundProject" ("id", "roundId", "projectId", "status", "addedAt")
+SELECT gen_random_uuid(), p."roundId", p."id", p."status", p."createdAt"
+FROM "Project" p;
+
+-- Add indexes and unique constraint
+CREATE UNIQUE INDEX "RoundProject_roundId_projectId_key" ON "RoundProject"("roundId", "projectId");
+CREATE INDEX "RoundProject_roundId_idx" ON "RoundProject"("roundId");
+CREATE INDEX "RoundProject_projectId_idx" ON "RoundProject"("projectId");
+CREATE INDEX "RoundProject_status_idx" ON "RoundProject"("status");
+
+-- Add foreign keys
+ALTER TABLE "RoundProject" ADD CONSTRAINT "RoundProject_roundId_fkey"
+  FOREIGN KEY ("roundId") REFERENCES "Round"("id") ON DELETE CASCADE ON UPDATE CASCADE;
+ALTER TABLE "RoundProject" ADD CONSTRAINT "RoundProject_projectId_fkey"
+  FOREIGN KEY ("projectId") REFERENCES "Project"("id") ON DELETE CASCADE ON UPDATE CASCADE;
+
+-- Step 4: Drop old columns from Project
+-- Drop the roundId foreign key constraint first
+ALTER TABLE "Project" DROP CONSTRAINT "Project_roundId_fkey";
+
+-- Drop the roundId index
+DROP INDEX IF EXISTS "Project_roundId_idx";
+
+-- Drop status index
+DROP INDEX IF EXISTS "Project_status_idx";
+
+-- Drop the columns
+ALTER TABLE "Project" DROP COLUMN "roundId";
+ALTER TABLE "Project" DROP COLUMN "status";
+
+-- Add programId index
+CREATE INDEX "Project_programId_idx" ON "Project"("programId");