feat: controller-owned allocator API on control-plane DB (Closes #600)

Add gitea_allocate_next_work and allocator_service routing policy on top of
the #613 ControlPlaneDB substrate. Workers get atomic assign+lease results
(or wait/no_safe_work/terminal-path outcomes) without self-selecting work
via file locks or comment-only leases. #612 remains downstream.

Closes #600

task_capability_map.py

@@ -139,6 +139,17 @@ TASK_CAPABILITY_MAP: dict[str, dict[str, str]] = {
         "permission": "gitea.pr.create",
         "role": "author",
     },
+    # #600: controller-owned allocator — any authenticated profile may call;
+    # routing enforces role match to selected work. Uses control-plane DB (#613).
+    "allocate_next_work": {
+        "permission": "gitea.read",
+        "role": "author",
+    },
+    "gitea_allocate_next_work": {
+        "permission": "gitea.read",
+        "role": "author",
+    },
+
     "reconcile_landed_pr": {
         "permission": "gitea.read",
         "role": "author",