refactor: tech debt batch 3 — type safety + assignment router split

#5 — Replaced 55x PrismaClient | any with proper Prisma types across 8 files
- Service files: PrismaClient | any → PrismaClient, tx: any → Prisma.TransactionClient
- Fixed 4 real bugs uncovered by typing:
  - mentor-workspace.ts: wrong FK fields (mentorAssignmentId → workspaceId, role → senderRole)
  - ai-shortlist.ts: untyped string passed to CompetitionCategory enum filter
  - result-lock.ts: unknown passed where Prisma.InputJsonValue required

#9 — Split assignment.ts (2,775 lines) into 6 focused files:
  - shared.ts (93 lines) — MOVABLE_EVAL_STATUSES, buildBatchNotifications, getCandidateJurors
  - assignment-crud.ts (473 lines) — 8 core CRUD procedures
  - assignment-suggestions.ts (880 lines) — AI suggestions + job runner
  - assignment-notifications.ts (138 lines) — 2 notification procedures
  - assignment-redistribution.ts (1,162 lines) — 8 reassign/transfer procedures
  - index.ts (15 lines) — barrel export with router merge, zero frontend changes

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

src/server/services/round-engine.ts

@@ -74,7 +74,7 @@ const VALID_PROJECT_TRANSITIONS: Record<string, string[]> = {
 export async function activateRound(
   roundId: string,
   actorId: string,
-  prisma: PrismaClient | any,
+  prisma: PrismaClient,
 ): Promise<RoundTransitionResult> {
   try {
     const round = await prisma.round.findUnique({
@@ -127,7 +127,7 @@ export async function activateRound(
       windowData.windowOpenAt = now
     }
 
-    const updated = await prisma.$transaction(async (tx: any) => {
+    const updated = await prisma.$transaction(async (tx: Prisma.TransactionClient) => {
       const result = await tx.round.update({
         where: { id: roundId },
         data: { status: 'ROUND_ACTIVE', ...windowData },
@@ -234,7 +234,7 @@ export async function activateRound(
 export async function closeRound(
   roundId: string,
   actorId: string,
-  prisma: PrismaClient | any,
+  prisma: PrismaClient,
 ): Promise<RoundTransitionResult> {
   try {
     const round = await prisma.round.findUnique({
@@ -267,7 +267,7 @@ export async function closeRound(
       }
     }
 
-    const updated = await prisma.$transaction(async (tx: any) => {
+    const updated = await prisma.$transaction(async (tx: Prisma.TransactionClient) => {
       const result = await tx.round.update({
         where: { id: roundId },
         data: { status: 'ROUND_CLOSED' },
@@ -383,7 +383,7 @@ export async function closeRound(
 export async function archiveRound(
   roundId: string,
   actorId: string,
-  prisma: PrismaClient | any,
+  prisma: PrismaClient,
 ): Promise<RoundTransitionResult> {
   try {
     const round = await prisma.round.findUnique({ where: { id: roundId } })
@@ -399,7 +399,7 @@ export async function archiveRound(
       }
     }
 
-    const updated = await prisma.$transaction(async (tx: any) => {
+    const updated = await prisma.$transaction(async (tx: Prisma.TransactionClient) => {
       const result = await tx.round.update({
         where: { id: roundId },
         data: { status: 'ROUND_ARCHIVED' },
@@ -456,7 +456,7 @@ export async function archiveRound(
 export async function reopenRound(
   roundId: string,
   actorId: string,
-  prisma: PrismaClient | any,
+  prisma: PrismaClient,
 ): Promise<RoundTransitionResult & { pausedRounds?: string[] }> {
   try {
     const round = await prisma.round.findUnique({
@@ -475,7 +475,7 @@ export async function reopenRound(
       }
     }
 
-    const result = await prisma.$transaction(async (tx: any) => {
+    const result = await prisma.$transaction(async (tx: Prisma.TransactionClient) => {
       // Pause any subsequent active rounds in the same competition
       const subsequentActiveRounds = await tx.round.findMany({
         where: {
@@ -601,7 +601,7 @@ export async function transitionProject(
   roundId: string,
   newState: ProjectRoundStateValue,
   actorId: string,
-  prisma: PrismaClient | any,
+  prisma: PrismaClient,
   options?: { adminOverride?: boolean },
 ): Promise<ProjectRoundTransitionResult> {
   try {
@@ -624,7 +624,7 @@ export async function transitionProject(
       return { success: false, errors: [`Project ${projectId} not found`] }
     }
 
-    const result = await prisma.$transaction(async (tx: any) => {
+    const result = await prisma.$transaction(async (tx: Prisma.TransactionClient) => {
       const now = new Date()
 
       // Upsert ProjectRoundState
@@ -722,7 +722,7 @@ export async function batchTransitionProjects(
   roundId: string,
   newState: ProjectRoundStateValue,
   actorId: string,
-  prisma: PrismaClient | any,
+  prisma: PrismaClient,
   options?: { adminOverride?: boolean },
 ): Promise<BatchProjectTransitionResult> {
   const succeeded: string[] = []
@@ -754,7 +754,7 @@ export async function batchTransitionProjects(
 
 export async function getProjectRoundStates(
   roundId: string,
-  prisma: PrismaClient | any,
+  prisma: PrismaClient,
 ) {
   const states = await prisma.projectRoundState.findMany({
     where: { roundId },
@@ -803,7 +803,7 @@ export async function getProjectRoundStates(
 export async function getProjectRoundState(
   projectId: string,
   roundId: string,
-  prisma: PrismaClient | any,
+  prisma: PrismaClient,
 ) {
   return prisma.projectRoundState.findUnique({
     where: { projectId_roundId: { projectId, roundId } },
@@ -823,7 +823,7 @@ export async function checkRequirementsAndTransition(
   projectId: string,
   roundId: string,
   actorId: string,
-  prisma: PrismaClient | any,
+  prisma: PrismaClient,
 ): Promise<{ transitioned: boolean; newState?: string }> {
   try {
     // Get all required FileRequirements for this round (legacy model)
@@ -939,7 +939,7 @@ export async function batchCheckRequirementsAndTransition(
   roundId: string,
   projectIds: string[],
   actorId: string,
-  prisma: PrismaClient | any,
+  prisma: PrismaClient,
 ): Promise<{ transitionedCount: number; projectIds: string[] }> {
   if (projectIds.length === 0) return { transitionedCount: 0, projectIds: [] }
 
@@ -1051,7 +1051,7 @@ export async function triggerInProgressOnActivity(
   projectId: string,
   roundId: string,
   actorId: string,
-  prisma: PrismaClient | any,
+  prisma: PrismaClient,
 ): Promise<void> {
   try {
     const prs = await prisma.projectRoundState.findUnique({
@@ -1078,7 +1078,7 @@ export async function checkEvaluationCompletionAndTransition(
   projectId: string,
   roundId: string,
   actorId: string,
-  prisma: PrismaClient | any,
+  prisma: PrismaClient,
 ): Promise<{ transitioned: boolean }> {
   try {
     const prs = await prisma.projectRoundState.findUnique({