refactor(feed): use PrismaClient type directly in assertPetOwnership

src/trpc/routers/feed.ts

@@ -4,13 +4,14 @@ import { TRPCError } from "@trpc/server";
 import { router, protectedProcedure } from "@/trpc/init";
 import { redis } from "@/lib/redis";
 import { getFeedPage } from "@/lib/feed-helpers";
+import type { PrismaClient } from "@prisma/client";
 
 /**
  * Ownership assertion: verifies petId belongs to ctx.userId.
  * Security (T-02-20): prevents feed spoofing via fabricated petId.
  */
 async function assertPetOwnership(
-  prisma: Parameters<typeof feedRouter.createCaller>[0]["prisma"],
+  prisma: PrismaClient,
   petId: string,
   userId: string
 ) {