tRPC Procedure Missing Input Validation

Description

tRPC procedures without .input() validation accept unvalidated payloads at runtime, enabling injection and type confusion attacks.

What Shoulder detects

Procedure '{procedure}' accepts user input but lacks .input() validation. Add Zod schema to validate runtime data.

How to fix

Add Zod schema validation with .input() to all procedures.

```typescript
import { z } from 'zod';

export const userRouter = router({
  getUser: publicProcedure
    .input(z.object({
      userId: z.number().int().positive()
    }))
    .query(async ({ input }) => {
      return await db.user.findUnique({ where: { id: input.userId } });
    })
});
```

Learn more: https://shoulder.dev/learn/typescript/cwe-20/missing-input-validation