feat: add live PR/issue queue dashboard to web UI (Closes #429)

Adds read-only /queue and /api/queue routes that load open PRs and issues
from the default registry project via gitea_auth, surface pagination proof,
and classify items with claimed/blocked/in-review/duplicate badges.

Co-Authored-By: Claude Opus 4.8 (1M context) <[email protected]>

webui/layout.py

@@ -4,6 +4,7 @@ from __future__ import annotations
 
 NAV_ITEMS = (
     ("/", "Home"),
+    ("/queue", "Queue"),
     ("/projects", "Projects"),
     ("/prompts", "Prompts"),
     ("/runtime", "Runtime"),
@@ -145,6 +146,20 @@ def render_page(*, title: str, body_html: str, extra_head: str = "") -> str:
     }}
     .copy-btn:hover {{ filter: brightness(1.08); }}
     .muted {{ color: var(--muted); }}
+    .badges {{ display: inline-flex; flex-wrap: wrap; gap: 0.35rem; margin-left: 0.5rem; }}
+    .badge {{
+      font-size: 0.72rem;
+      padding: 0.1rem 0.45rem;
+      border-radius: 999px;
+      border: 1px solid var(--border);
+      color: var(--muted);
+      text-transform: lowercase;
+    }}
+    .badge-claimed {{ color: #8fd19e; border-color: #3d6b4a; }}
+    .badge-blocked {{ color: #f0a8a8; border-color: #7a3b3b; }}
+    .badge-in-review {{ color: #9ec8f0; border-color: #3d5f7a; }}
+    .badge-duplicate {{ color: #e0c27a; border-color: #6b5730; }}
+    .badge-stale {{ color: #c9b8e8; border-color: #5a4a78; }}
   </style>
   {extra_head}
 </head>