fix(profiles): canonical reconciler ops and guard raw branch delete (#687)

Address REQUEST_CHANGES on PR #688:

- migrate_profiles: emit fully canonical reconciler/author/reviewer defaults;
  canonicalize explicit ops; fail if reconciler loses required pr.close/read
- gitea_delete_branch: deny reconciler (and non-author roles); refuse
  preservation/protected branches before any API call
- gitea_cleanup_merged_pr_branch: require reconciler role only; block
  preservation/evidence branches via branch_cleanup_guard
- docs: end-to-end operator runbook for profile migrate/apply/reconnect/cleanup
- tests: migration canonicalization, idempotency, raw-delete denial, guarded
  cleanup success and unmerged/preserve rejections

Closes #687.

gitea_mcp_server.py

@@ -5925,6 +5925,65 @@ def gitea_delete_branch(
             "permission_report": _permission_block_report("gitea.branch.delete"),
         }
 
+    # Possessing gitea.branch.delete alone is not enough for arbitrary deletion.
+    # task_capability_map maps delete_branch → author; reconciler must use the
+    # guarded cleanup_merged_pr_branch path only (#687 / #514).
+    profile = get_profile()
+    active_role = _profile_role_kind(profile)
+    required_role = task_capability_map.required_role("delete_branch")
+    if active_role == "reconciler":
+        return {
+            "success": False,
+            "performed": False,
+            "required_permission": "gitea.branch.delete",
+            "required_role_kind": required_role,
+            "active_role_kind": active_role,
+            "reasons": [
+                "reconciler profile cannot use raw gitea_delete_branch; "
+                "use gitea_cleanup_merged_pr_branch for a fully merged PR "
+                "source branch only (fail closed)"
+            ],
+            "exact_next_action": (
+                "Call gitea_cleanup_merged_pr_branch with pr_number, the "
+                "exact PR head branch, and confirmation "
+                "'CLEANUP MERGED PR <n> BRANCH <branch>' after capability "
+                "resolve for cleanup_merged_pr_branch."
+            ),
+            "permission_report": _permission_block_report("gitea.branch.delete"),
+        }
+    if active_role != required_role:
+        return {
+            "success": False,
+            "performed": False,
+            "required_permission": "gitea.branch.delete",
+            "required_role_kind": required_role,
+            "active_role_kind": active_role,
+            "reasons": [
+                f"Active profile role '{active_role}' cannot perform "
+                f"{required_role} task 'delete_branch' even when "
+                "gitea.branch.delete is present (fail closed)"
+            ],
+            "permission_report": _permission_block_report("gitea.branch.delete"),
+        }
+
+    if branch_cleanup_guard.is_preservation_or_evidence_branch(branch):
+        return {
+            "success": False,
+            "performed": False,
+            "required_permission": "gitea.branch.delete",
+            "reasons": [
+                f"branch '{branch}' is a preservation/evidence branch and "
+                "cannot be deleted (fail closed)"
+            ],
+        }
+    if branch in branch_cleanup_guard.PROTECTED_BRANCHES:
+        return {
+            "success": False,
+            "performed": False,
+            "required_permission": "gitea.branch.delete",
+            "reasons": [f"branch '{branch}' is protected (fail closed)"],
+        }
+
     audit_allowed, audit_reasons = (
         audit_reconciliation_mode.check_audit_mutation_allowed("delete_branch")
     )
@@ -5976,18 +6035,20 @@ def gitea_cleanup_merged_pr_branch(
         }
 
     profile = get_profile()
-    active_role = _role_kind(
-        profile.get("allowed_operations", []),
-        profile.get("forbidden_operations", []),
-    )
-    if active_role == "reviewer":
+    active_role = _profile_role_kind(profile)
+    # cleanup_merged_pr_branch is reconciler-owned (task_capability_map).
+    # Author/reviewer/merger must not reach this path even if they somehow
+    # hold gitea.branch.delete.
+    if active_role != "reconciler":
         return {
             "success": False,
             "performed": False,
             "required_permission": "gitea.branch.delete",
+            "required_role_kind": "reconciler",
+            "active_role_kind": active_role,
             "reasons": [
-                "reviewer profile is not authorized for merged branch cleanup "
-                "(fail closed)"
+                f"profile role '{active_role}' is not authorized for merged "
+                "branch cleanup; required role is reconciler (fail closed)"
             ],
             "permission_report": _permission_block_report("gitea.branch.delete"),
         }
@@ -11269,6 +11330,8 @@ def gitea_resolve_task_capability(
         "gitea_commit_files",
         "address_pr_change_requests",
         "delete_branch",
+        "cleanup_merged_pr_branch",
+        "reconciliation_cleanup",
         "work_issue",
         "work-issue",
     }