Fix QA review 2719: optional coatType/petSizeCategory, CoatType union, null guards

- Make coatType and petSizeCategory optional on Pet (?:) — they may not be set
- Remove "single" and "short" from COAT_TYPES (not in CoatType union)
- Use { name: "Add" } instead of /add/i to target the + button specifically
- Add optional chaining to puppyCutSpans[0]?.closest() (noUncheckedIndexedAccess)
- Add optional chaining to petsData[0]?.id ?? "" in PetProfiles

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

src/__tests__/PetForm.test.tsx

@@ -65,7 +65,7 @@ describe("PetForm", () => {
     render(<PetForm pet={BASE_PET} onSave={onSave} onCancel={onCancel} />);
     const input = screen.getByPlaceholderText(/type a cut name/i);
     fireEvent.change(input, { target: { value: "Teddy Bear" } });
-    fireEvent.click(screen.getByRole("button", { name: /add/i }));
+    fireEvent.click(screen.getByRole("button", { name: "Add" }));
     expect(screen.getByText("Teddy Bear")).toBeTruthy();
   });
 
@@ -76,7 +76,7 @@ describe("PetForm", () => {
     };
     render(<PetForm pet={petWithCuts} onSave={onSave} onCancel={onCancel} />);
     const puppyCutSpans = screen.getAllByText("Puppy Cut");
-    const puppyCutTag = puppyCutSpans[0].closest("span");
+    const puppyCutTag = puppyCutSpans[0]?.closest("span");
     if (!puppyCutTag) return;
     const removeBtn = puppyCutTag.querySelector("button");
     if (!removeBtn) return;