refactor(auth): remove Guest role from user type system

Remove all references to 'Guest' user type from the codebase, simplifying the role system to only support 'Admin' and 'User' roles.

Changes:
- Update type definitions to exclude 'Guest' from UserType
- Remove isGuest() method from SessionManager
- Remove Guest-specific logic from update services
- Update all type assertions from 'Admin | User | Guest' to 'Admin | User'
- Remove Guest UI styling from UserSelectionDialog
- Replace Guest fallback with ValidationError in settings handler

Error handling:
- Zod schema now rejects 'Guest' as invalid user type
- TypeScript will fail compilation if 'Guest' is referenced
- Runtime errors occur if database contains Guest users

No database migration needed (confirmed: no Guest users exist)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/main/services/update/update-catalog-service.ts

@@ -29,7 +29,7 @@ export class UpdateCatalogService {
 
   public getDialogCatalog(status: UpdateStatus, catalog: UpdateCatalog): UpdateDialogCatalog {
     const currentUserType = status.currentUserType
-    if (!status.enabled || !currentUserType || currentUserType === 'Guest') {
+    if (!status.enabled || !currentUserType) {
       return { mode: 'disabled' }
     }
 

src/main/services/update/update-service.ts

@@ -106,7 +106,7 @@ export class UpdateService {
     this.ensureInitialized()
     this.status.currentUserType = userType
 
-    if (!this.status.enabled || !userType || userType === 'Guest') {
+    if (!this.status.enabled || !userType) {
       this.clearPolling()
       this.catalog = { stable: [], preview: [] }
       this.publishStatus({

src/main/services/user/bip-users-dao.ts

@@ -139,7 +139,7 @@ export class BIPUsersDAO {
           return {
             id: row.ID as number,
             username: row.UserName as string,
-            userType: row.UserType as 'Admin' | 'User' | 'Guest'
+            userType: row.UserType as 'Admin' | 'User'
           }
         }
         return null
@@ -157,7 +157,7 @@ export class BIPUsersDAO {
           return {
             id: row.ID as number,
             username: row.UserName as string,
-            userType: row.UserType as 'Admin' | 'User' | 'Guest'
+            userType: row.UserType as 'Admin' | 'User'
           }
         }
         return null
@@ -198,7 +198,7 @@ export class BIPUsersDAO {
           return {
             id: row.ID as number,
             username: row.UserName as string,
-            userType: row.UserType as 'Admin' | 'User' | 'Guest'
+            userType: row.UserType as 'Admin' | 'User'
           }
         }
         return null
@@ -216,7 +216,7 @@ export class BIPUsersDAO {
           return {
             id: row.ID as number,
             username: row.UserName as string,
-            userType: row.UserType as 'Admin' | 'User' | 'Guest'
+            userType: row.UserType as 'Admin' | 'User'
           }
         }
         return null
@@ -254,7 +254,7 @@ export class BIPUsersDAO {
       return result.rows.map((row) => ({
         id: row.ID as number,
         username: row.UserName as string,
-        userType: row.UserType as 'Admin' | 'User' | 'Guest',
+        userType: row.UserType as 'Admin' | 'User',
         createTime: row.CreateTime as Date | undefined
       }))
     } catch (error) {
@@ -270,7 +270,7 @@ export class BIPUsersDAO {
    * Create a new user
    * @param username - The username (must be unique)
    * @param password - The password
-   * @param userType - User type ('Admin', 'User', or 'Guest')
+   * @param userType - User type ('Admin' or 'User')
    * @param computerName - Optional computer name for silent login
    * @returns True if successful
    */

src/main/services/user/session-manager.ts

@@ -126,13 +126,6 @@ export class SessionManager {
     return this.currentUser?.userType === 'Admin'
   }
 
-  /**
-   * Check if the current user is a guest
-   */
-  public isGuest(): boolean {
-    return this.currentUser?.userType === 'Guest'
-  }
-
   /**
    * Get the current username
    */