feat: add pet size/coat to booking flow with buffer-aware availability

- Add petSizeCategory and petCoatType dropdowns to booking wizard
  (after breed field, optional but encouraged)
- Pass selected values to GET /availability as query params
- large/x-large pets add service.defaultBufferMinutes to slot calculation
  and appointment end time (buffer never shown to client)
- POST /appointments saves size/coat to pet record
- Confirmation step shows total duration (service + buffer if applicable)

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

packages/db/src/schema.ts

@@ -151,19 +151,9 @@ export const pets = pgTable(
     name: text("name").notNull(),
     species: text("species").notNull(),
     breed: text("breed"),
-    weightKg: numeric("weight_kg", { precision: 5, scale: 2 }),
-    dateOfBirth: timestamp("date_of_birth"),
-    healthAlerts: text("health_alerts"),
-    groomingNotes: text("grooming_notes"),
-    cutStyle: text("cut_style"),
-    shampooPreference: text("shampoo_preference"),
-    specialCareNotes: text("special_care_notes"),
-    customFields: jsonb("custom_fields").$type<Record<string, string>>().notNull().default({}),
-    photoKey: text("photo_key"),
-    photoUploadedAt: timestamp("photo_uploaded_at"),
-    image: text("image"),
     sizeCategory: petSizeCategoryEnum("size_category"),
     coatType: coatTypeEnum("coat_type"),
+    weightKg: numeric("weight_kg", { precision: 5, scale: 2 }),
     createdAt: timestamp("created_at").notNull().defaultNow(),
     updatedAt: timestamp("updated_at").notNull().defaultNow(),
   },