feat: add health alerts field and delete actions for pets and clients

- Add health_alerts column to pets table (migration 0001)
- Update DB schema, shared types, and API Zod validation
- Show health alerts prominently (red badge) in pet cards
- Add health alerts field to pet form with allergy/condition placeholder
- Add delete button per pet with confirmation dialog
- Add delete client button with cascade warning

Closes groombook/groombook#2

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

packages/types/src/index.ts

@@ -27,6 +27,7 @@ export interface Pet {
   breed: string | null;
   weightKg: number | null;
   dateOfBirth: string | null;
+  healthAlerts: string | null;
   groomingNotes: string | null;
   createdAt: string;
   updatedAt: string;