refactor: remove dead user validation code and simplify mock

Removed the now-empty userValidation.js and its test file since the
validation function was reduced to a no-op. Cleaned up the callers in
UserCreate and UserEdit that referenced it. Simplified the mock
GetUserLibraries fallback to delegate to GetAll instead of duplicating
its logic, and removed redundant comments.

tests/mock_library_repo.go

@@ -267,7 +267,6 @@ func (m *MockLibraryRepo) GetUserLibraries(ctx context.Context, userID string) (
 	if userID == "non-existent" {
 		return nil, model.ErrNotFound
 	}
-	// If per-user tracking is set, return only the assigned libraries
 	if m.UserLibraries != nil {
 		ids, ok := m.UserLibraries[userID]
 		if !ok {
@@ -284,15 +283,7 @@ func (m *MockLibraryRepo) GetUserLibraries(ctx context.Context, userID string) (
 		})
 		return libraries, nil
 	}
-	// Fallback: return all libraries
-	var libraries model.Libraries
-	for _, lib := range m.Data {
-		libraries = append(libraries, lib)
-	}
-	slices.SortFunc(libraries, func(a, b model.Library) int {
-		return a.ID - b.ID
-	})
-	return libraries, nil
+	return m.GetAll()
 }
 
 func (m *MockLibraryRepo) SetUserLibraries(ctx context.Context, userID string, libraryIDs []int) error {
@@ -305,13 +296,11 @@ func (m *MockLibraryRepo) SetUserLibraries(ctx context.Context, userID string, l
 	if userID == "admin-1" {
 		return fmt.Errorf("%w: cannot manually assign libraries to admin users", model.ErrValidation)
 	}
-	// Validate all library IDs exist
 	for _, id := range libraryIDs {
 		if _, exists := m.Data[id]; !exists {
 			return fmt.Errorf("%w: library ID %d does not exist", model.ErrValidation, id)
 		}
 	}
-	// Store per-user assignments
 	if m.UserLibraries == nil {
 		m.UserLibraries = make(map[string][]int)
 	}

ui/src/user/UserCreate.jsx

@@ -51,17 +51,9 @@ const UserCreate = (props) => {
     [mutate, notify, redirect],
   )
 
-  // Custom validation function
-  const validateUserForm = (values) => {
-    const errors = {}
-    // Library selection is optional for non-admin users since they will be auto-assigned to default libraries
-    // No validation required for library selection
-    return errors
-  }
-
   return (
     <Create title={<Title subTitle={title} />} {...props}>
-      <SimpleForm save={save} validate={validateUserForm} variant={'outlined'}>
+      <SimpleForm save={save} variant={'outlined'}>
         <TextInput
           spellCheck={false}
           source="userName"

ui/src/user/UserEdit.jsx

@@ -24,7 +24,6 @@ import { Typography } from '@material-ui/core'
 import { Title } from '../common'
 import DeleteUserButton from './DeleteUserButton'
 import { LibrarySelectionField } from './LibrarySelectionField.jsx'
-import { validateUserForm } from './userValidation'
 
 const useStyles = makeStyles({
   toolbar: {
@@ -104,18 +103,12 @@ const UserEdit = (props) => {
     [mutate, notify, permissions, redirect, refresh],
   )
 
-  // Custom validation function
-  const validateForm = (values) => {
-    return validateUserForm(values, translate)
-  }
-
   return (
     <Edit title={<UserTitle />} undoable={false} {...props}>
       <SimpleForm
         variant={'outlined'}
         toolbar={<UserToolbar showDelete={canDelete} />}
         save={save}
-        validate={validateForm}
       >
         {permissions === 'admin' && (
           <TextInput

ui/src/user/userValidation.js

@@ -1,5 +0,0 @@
-// User form validation utilities
-export const validateUserForm = (_values, _translate) => {
-  const errors = {}
-  return errors
-}

ui/src/user/userValidation.test.js

@@ -1,43 +0,0 @@
-import { describe, it, expect, vi } from 'vitest'
-import { validateUserForm } from './userValidation'
-
-describe('User Validation Utilities', () => {
-  const mockTranslate = vi.fn((key) => key)
-
-  describe('validateUserForm', () => {
-    it('should not return errors for admin users', () => {
-      const values = {
-        isAdmin: true,
-        libraryIds: [],
-      }
-      const errors = validateUserForm(values, mockTranslate)
-      expect(errors).toEqual({})
-    })
-
-    it('should not return errors for non-admin users with libraries', () => {
-      const values = {
-        isAdmin: false,
-        libraryIds: [1, 2, 3],
-      }
-      const errors = validateUserForm(values, mockTranslate)
-      expect(errors).toEqual({})
-    })
-
-    it('should not return errors for non-admin users without libraries', () => {
-      const values = {
-        isAdmin: false,
-        libraryIds: [],
-      }
-      const errors = validateUserForm(values, mockTranslate)
-      expect(errors).toEqual({})
-    })
-
-    it('should not return errors for non-admin users with undefined libraryIds', () => {
-      const values = {
-        isAdmin: false,
-      }
-      const errors = validateUserForm(values, mockTranslate)
-      expect(errors).toEqual({})
-    })
-  })
-})