Merge cms-upload-userid-capture into dev (capture upload-form user id at init so mid-session token expiry can't discard a composed release)

DeepDrftManager/Components/Pages/Tracks/BatchUpload.razor

@@ -129,6 +129,11 @@
     // Set true once the admin has acknowledged the missing-hero warning, so a second submit proceeds.
     private bool _heroWarningAcknowledged;
 
+    // Captured once at component initialization on the live interactive circuit, while the token
+    // is known-good, so a mid-session token expiry at submit time cannot discard a long-composed
+    // release. Only assigned when the id parses successfully.
+    private long? _createdByUserId;
+
     private string _albumName = string.Empty;
     private string _artist = string.Empty;
     private string _genre = string.Empty;
@@ -156,6 +161,19 @@
         }
     }
 
+    protected override async Task OnInitializedAsync()
+    {
+        // Capture the user id once at load, while the token is known-good. The CMS host runs with
+        // prerender: false (InteractiveServer), so this is the single init pass — auth state is
+        // fully available. The page is [Authorize]-gated, so the parse should always succeed.
+        var authState = await AuthStateProvider.GetAuthenticationStateAsync();
+        var userIdValue = authState.User.FindFirstValue(ClaimTypes.NameIdentifier);
+        if (long.TryParse(userIdValue, out var userId))
+        {
+            _createdByUserId = userId;
+        }
+    }
+
     // Switching to a single-track medium collapses any multi-track selection to the first row so the
     // single-track invariant holds before submit. The predicate reads the same MediumRules cardinality
     // declaration the upload service enforces, so the form and the domain cannot drift.
@@ -275,13 +293,12 @@
             }
         }
 
-        var authState = await AuthStateProvider.GetAuthenticationStateAsync();
-        var userIdValue = authState.User.FindFirstValue(ClaimTypes.NameIdentifier);
-        if (!long.TryParse(userIdValue, out var createdByUserId))
+        if (_createdByUserId is not long createdByUserId)
         {
-            // The page is gated by [Authorize] under the Admin role, so a missing or
-            // unparseable id here is a configuration bug, not normal client state.
-            Logger.LogError("Authenticated user has no parseable NameIdentifier claim: {Value}", userIdValue);
+            // _createdByUserId is set at component initialization from the authenticated principal.
+            // A null here means the id was unavailable even at load — a genuine configuration bug,
+            // since the page is [Authorize]-gated.
+            Logger.LogError("User id was not captured at initialization — NameIdentifier claim missing or unparseable.");
             _errorMessage = "Your session is missing a valid identifier. Please sign in again.";
             return;
         }