fix(test): fix petsExtendedFields vi.mock hoisting and invalid UUIDs

Two pre-existing bugs prevented petsExtendedFields.test.ts from running:

1. vi.mock factory referenced bare `and`, `eq`, `exists`, `or` variables
   that are undefined at hoist time — replaced with inline mock functions
2. CLIENT_ID/PET_ID used non-UUID strings but Zod schema requires uuid()

All 36 test files (521 tests) now pass.

Co-Authored-By: Paperclip <noreply@paperclip.ing>

apps/api/src/__tests__/petsExtendedFields.test.ts

@@ -21,8 +21,8 @@ const MANAGER: StaffRow = {
 
 // ─── Mutable mock state ───────────────────────────────────────────────────────
 
-const CLIENT_ID = "client-uuid-extended";
-const PET_ID = "pet-uuid-extended";
+const CLIENT_ID = "a0000000-0000-4000-8000-000000000001";
+const PET_ID = "b0000000-0000-4000-8000-000000000002";
 
 let petRows: Record<string, unknown>[] = [];
 let appointmentRows: Record<string, unknown>[] = [];
@@ -163,10 +163,10 @@ vi.mock("../db", () => {
     }),
     pets,
     appointments,
-    and,
-    eq,
-    exists,
-    or,
+    and: (...conds: unknown[]) => conds,
+    eq: (col: unknown, val: unknown) => ({ col, val }),
+    exists: (q: unknown) => q,
+    or: (...conds: unknown[]) => conds,
   };
 });