fix(auth): route delete_branch capability to the reconciler role (Closes #729)

Remote post-merge branch deletion was blocked because the capability
resolver classified delete_branch as an author-role task while
gitea.branch.delete is granted only to prgs-reconciler. No configured
profile could satisfy both the permission gate and the role gate, so
every deletion failed closed with performed=false.

Re-home delete_branch from the author role to the reconciler role in
both single-source-of-truth maps:
  - task_capability_map.TASK_CAPABILITY_MAP["delete_branch"].role
  - role_session_router: TASK_REQUIRED_ROLE + AUTHOR_TASKS/RECONCILER_TASKS

resolve_task_capability("delete_branch") now resolves to prgs-reconciler.
In gitea_delete_branch, the reconciler is now the delete-capable role and
performs raw deletion through the existing reconciliation-cleanup-phase
authorization gate (operator approval + safe_to_delete proof) plus the
preservation/protected guards; the prior reconciler->cleanup redirect is
removed as it would orphan that guarded flow. Author, reviewer, and
merger stay denied by the permission gate and the required-role gate.
gitea_cleanup_merged_pr_branch remains a separate reconciler-owned path
with independent merged/ancestry/ownership verification.

Tests: reconciler resolves + performs eligible deletion; author/reviewer/
merger denied even when holding the permission; protected/preservation
branches remain fail-closed; both role maps asserted in agreement.
Updated pre-existing tests that encoded the superseded author-delete /
#687 reconciler-redirect contract. Full suite: 3190 passed, 6 skipped,
1 pre-existing unrelated failure (test_issue_702 create_pr stale-binding).

Co-Authored-By: Claude Opus 4.8 (1M context) <[email protected]>
Claude-Session: https://claude.ai/code/session_01UracxyRHQw49rZBaexHdft

tests/test_branch_cleanup_guard.py

@@ -257,22 +257,27 @@ class TestMergedPrBranchCleanupTool(unittest.TestCase):
         ]
         self.assertFalse(delete_calls)
 
-    def test_reconciler_with_branch_delete_cannot_raw_delete(self):
-        """#687: reconciler + gitea.branch.delete still cannot call raw delete."""
+    def test_reconciler_with_branch_delete_can_raw_delete(self):
+        """#729: delete_branch is re-homed from author to reconciler. The
+        reconciler is the delete-capable role and performs raw deletion of an
+        eligible (non-preservation, non-protected) branch — superseding the
+        #687 redirect that previously blocked it."""
         patch(
             "mcp_server.get_profile",
             return_value=dict(RECONCILER_WITH_DELETE),
         ).start()
+        mcp_server.record_preflight_check("whoami")
+        mcp_server.record_preflight_check("capability", resolved_role="reconciler")
+        self.mock_api.return_value = {}
         res = gitea_delete_branch(
             branch="fix/issue-683-workflow-guard-hardening",
             remote="prgs",
         )
-        self.assertFalse(res.get("success", True))
-        self.assertFalse(res.get("performed", True))
-        reasons = " ".join(res.get("reasons") or [])
-        self.assertIn("raw gitea_delete_branch", reasons)
-        self.assertIn("cleanup_merged_pr_branch", reasons)
-        self.mock_api.assert_not_called()
+        self.assertTrue(res.get("success"))
+        delete_calls = [
+            call for call in self.mock_api.call_args_list if call.args[0] == "DELETE"
+        ]
+        self.assertTrue(delete_calls)
 
     def test_reconciler_raw_delete_denies_preservation_branch(self):
         patch(
@@ -286,17 +291,18 @@ class TestMergedPrBranchCleanupTool(unittest.TestCase):
         self.assertFalse(res.get("performed", True))
         self.mock_api.assert_not_called()
 
-    def test_author_with_branch_delete_role_ok_but_preserve_blocked(self):
-        """Author role may use raw delete path when permitted; preserve fails closed."""
+    def test_reconciler_raw_delete_role_ok_but_preserve_blocked(self):
+        """#729: reconciler role may use raw delete path when permitted;
+        preservation branch still fails closed."""
         patch(
             "mcp_server.get_profile",
             return_value={
-                "profile_name": "prgs-author",
-                "role": "author",
+                "profile_name": "prgs-reconciler",
+                "role": "reconciler",
                 "allowed_operations": [
                     "gitea.read",
-                    "gitea.pr.create",
-                    "gitea.branch.push",
+                    "gitea.issue.comment",
+                    "gitea.pr.comment",
                     "gitea.branch.delete",
                 ],
                 "forbidden_operations": ["gitea.pr.approve", "gitea.pr.merge"],