fix(webui): suppress empty queue copy on fetch failure (#458)

When Gitea credentials are missing or the queue fetch fails closed,
show "Not loaded" instead of "No open items." and keep pagination
marked unavailable. Successful empty inventories still show the empty
state with complete pagination proof.

Closes #458

webui/queue_views.py

@@ -38,7 +38,13 @@ def _queue_table(
     title: str,
     items: tuple[QueueItem, ...],
     columns: tuple[tuple[str, str], ...],
+    fetch_failed: bool = False,
 ) -> str:
+    if fetch_failed:
+        return (
+            f"<h3>{html.escape(title)}</h3>"
+            "<p class='muted'>Not loaded — queue fetch did not complete.</p>"
+        )
     if not items:
         return f"<h3>{html.escape(title)}</h3><p class='muted'>No open items.</p>"
 
@@ -73,9 +79,11 @@ def render_queue_page(snapshot: QueueSnapshot) -> str:
             f"{html.escape(snapshot.fetch_error)}</p></div>"
         )
 
+    fetch_failed = bool(snapshot.fetch_error)
     pr_section = _queue_table(
         title="Open pull requests",
         items=snapshot.prs,
+        fetch_failed=fetch_failed,
         columns=(
             ("number", "#"),
             ("title", "Title"),
@@ -88,6 +96,7 @@ def render_queue_page(snapshot: QueueSnapshot) -> str:
     issue_section = _queue_table(
         title="Open issues",
         items=snapshot.issues,
+        fetch_failed=fetch_failed,
         columns=(
             ("number", "#"),
             ("title", "Title"),