docs(agents): add per-package AGENTS.md for all core-* packages

packages/core-trpc/AGENTS.md

@@ -0,0 +1,54 @@
+# AGENTS.md — core-trpc
+
+Frontend tRPC platform providing the client and framework-specific providers (Next.js, TanStack). Bridges typed backend (`@repo/core-api`) to frontend applications.
+
+## Responsibilities
+
+- **Create tRPC React client** — `createTRPCReact<AppRouter>()` for use in React apps
+- **Query client factory** — TanStack React Query setup per app
+- **Framework-specific providers** — Next.js App Router provider + TanStack Start provider
+- **No business logic** — purely framework integration
+
+## Must NOT import
+
+- Any feature package (`@repo/auth`, `@repo/blog`, etc.)
+- Any app package
+- `@repo/core-api`, `@repo/core-cms`, `@repo/core-ui`
+
+## Public exports
+
+From `package.json`:
+- `.` — client + query client factory
+- `./next` — Next.js App Router provider
+- `./tanstack` — TanStack Start provider
+
+Example usage:
+```typescript
+// In Next.js app
+import { TrpcProvider } from "@repo/core-trpc/next";
+
+// In TanStack Start app
+import { TrpcProvider } from "@repo/core-trpc/tanstack";
+
+// In client components
+import { useTRPC } from "@repo/core-trpc";
+const trpc = useTRPC();
+```
+
+## Test conventions
+
+- No unit tests (provider layer)
+- Verify at app boot: `pnpm dev --filter @repo/web-next` or `pnpm dev --filter @repo/web-tanstack` succeeds
+- Verify client type safety: `pnpm typecheck` confirms `AppRouter` is imported and typed correctly
+
+## Structure
+
+```
+src/
+  client.ts                  # createTRPCReact<AppRouter>()
+  query-client.ts            # makeQueryClient()
+  providers/
+    next-provider.tsx        # 'use client' provider for Next.js
+    tanstack-provider.tsx    # Provider for TanStack Start
+  index.ts                   # re-exports client + factories
+```