Redesign login UI, add theme toggle, refactor user update

- Redesigned login page with two-panel layout and branding
- Added HexaDistro logo and theme toggle to sidebar/header
- Refactored user update: roles via update endpoint, removed assignRole API/controller
- Extended UpdateUserRequest for username, role, password changes
- UserService.UpdateAsync syncs changes with AuthHex, with rollback
- Stock balances client dedupes by itemId-locationId
- Middleware matcher excludes static assets from auth checks
- Improved localStorage clearing for user context
- Added lucide-react for icons
- Minor UI/code cleanups for consistency and UX

Distribution/Features/User/UserDTOs.cs

@@ -9,7 +9,12 @@ public record CreateUserRequest(
     Guid RoleId,
     Guid? ReportsToUserId);
 
-public record UpdateUserRequest(string FullName);
+public record UpdateUserRequest(
+    string FullName,
+    string? Username = null,
+    Guid? RoleId = null,
+    string? CurrentPassword = null,
+    string? NewPassword = null);
 
 public record AssignUserRoleRequest(Guid RoleId);