fix(profile): make useProfileEdit safe outside ProfileEditProvider (#318)

IdentityCard is used on events, embed, and homepage pages that don't
have a ProfileEditProvider. The hook now returns safe defaults (non-owner,
no preview) instead of throwing, fixing the Docker build failure.

src/components/profile-edit-provider.tsx

···
   );
 }
 
+const NO_OP = () => {};
+const NO_OP_RESULT = { success: false } as never;
+
+/** Safe defaults when used outside a ProfileEditProvider (e.g. embed, events, homepage). */
+const DEFAULT_CONTEXT: ProfileEditContextValue = {
+  profile: {} as Profile,
+  isActualOwner: false,
+  previewMode: false,
+  togglePreview: NO_OP,
+  updateProfile: NO_OP,
+  addItem: NO_OP,
+  updateItem: NO_OP,
+  removeItem: NO_OP,
+};
+
 export function useProfileEdit(): ProfileEditContextValue {
   const context = useContext(ProfileEditContext);
-  if (context === null) {
-    throw new Error('useProfileEdit must be used within a ProfileEditProvider');
-  }
-  return context;
+  return context ?? DEFAULT_CONTEXT;
 }

tests/components/profile-edit-provider.test.tsx

···
     expect(result.current.profile.education[0]?.institution).toBe('Stanford');
   });
 
-  it('throws when useProfileEdit is used outside provider', () => {
-    expect(() => {
-      renderHook(() => useProfileEdit());
-    }).toThrow('useProfileEdit must be used within a ProfileEditProvider');
+  it('returns safe defaults when useProfileEdit is used outside provider', () => {
+    const { result } = renderHook(() => useProfileEdit());
+    expect(result.current.isActualOwner).toBe(false);
+    expect(result.current.previewMode).toBe(false);
   });
 });