fix(event): remove all any casts — typed authenticate, user.id, and Prisma error narrowing (#595)

* fix(event): remove all �ny casts, use typed authenticate and Prisma narrowing

- Replace 3× 
equest.server as any / (app as any).authenticate preHandler boilerplate with �pp.authenticate — already declared on FastifyInstance in src/types/fastify.d.ts, consistent with follow.ts / team.ts pattern
- Replace 3× (request.user as any).id with 
equest.user.id — covered by the FastifyJWT augmentation (user: { id: string; username: string })
- Replace 2× catch (error: any) with catch (error: unknown) + instanceof Prisma.PrismaClientKnownRequestError narrowing before .code access (P2002 join-duplicate → 409, P2025 leave-not-found → 404)
- Replace (error as Error).message with getErrorMessage(error) from the shared error utility already used in follow.ts / connect.ts
- Update event.test.ts: construct Prisma error mocks with
ew Prisma.PrismaClientKnownRequestError(...) so instanceof narrowing resolves correctly in tests; import Prisma alongside PrismaClient

* fixed

* fixed again

* fix: resolve lint issues in event routes and tests

---------

Signed-off-by: Srejoye Saha <sahasrejoye2005@gmail.com>

Author: Srejoye

apps/backend/src/__tests__/event.test.ts

@@ -1,10 +1,9 @@
-import Fastify from 'fastify';
+import { type PrismaClient, Prisma } from '@prisma/client';
+import Fastify, { type FastifyInstance } from 'fastify';
 import { describe, it, expect, beforeEach, afterEach, vi } from 'vitest';
 
 import { eventRoutes } from '../routes/event';
 
-import type { PrismaClient } from '@prisma/client';
-import type { FastifyInstance,LightMyRequestResponse } from 'fastify';
 
 // ─── Shared mock data ────────────────────────────────────────────────────────
 
@@ -107,7 +106,7 @@ async function createEvent(
   app: FastifyInstance,
   body: Record<string, unknown>,
   authenticated = true,
-): Promise<LightMyRequestResponse>  {
+): Promise<Awaited<ReturnType<FastifyInstance['inject']>>> {
   return app.inject({
     method: 'POST',
     url: '/api/events',
@@ -367,9 +366,10 @@ describe('Events API', () => {
     it('409 — returns 409 when user already joined the event', async () => {
       prismaMock.event.findUnique.mockResolvedValue(MOCK_EVENT);
       // Prisma unique constraint error
-      const uniqueError = Object.assign(new Error('Unique constraint'), {
-        code: 'P2002',
-      });
+      const uniqueError = new Prisma.PrismaClientKnownRequestError(
+          'Unique constraint failed',
+          { code: 'P2002', clientVersion: '6.0.0' },
+      );
       prismaMock.eventAttendee.create.mockRejectedValue(uniqueError);
 
       const res = await app.inject({
@@ -452,9 +452,10 @@ describe('Events API', () => {
     it('404 — returns 404 when user was never an attendee (P2025)', async () => {
       prismaMock.event.findUnique.mockResolvedValue(MOCK_EVENT);
       // Prisma record-not-found error
-      const notFoundError = Object.assign(new Error('Record not found'), {
-        code: 'P2025',
-      });
+      const notFoundError = new Prisma.PrismaClientKnownRequestError(
+          'Record not found',
+          { code: 'P2025', clientVersion: '6.0.0' },
+      );
       prismaMock.eventAttendee.delete.mockRejectedValue(notFoundError);
 
       const res = await app.inject({
@@ -488,13 +489,13 @@ describe('Events API', () => {
     /** Builds a raw EventAttendee row as Prisma returns it (with nested user) */
     function makeAttendeeRow(
       profile: typeof MOCK_USER_PROFILE | typeof MOCK_OTHER_USER_PROFILE,
-          ) : {
-        id: string;
-        userId: string;
-        eventId: string;
-        joinedAt: Date;
-        user: typeof MOCK_USER_PROFILE | typeof MOCK_OTHER_USER_PROFILE;
-      }  {
+    ): {
+      id: string;
+      userId: string;
+      eventId: string;
+      joinedAt: Date;
+      user: typeof profile;
+    } {
       return {
         id: `attendee-${profile.id}`,
         userId: profile.id,