feat: gate reconciliation audit mode from unauthorized cleanup (Closes #419)

Add audit vs cleanup phase tracking so reconciliation audits stay read-only
unless cleanup is explicitly authorized with delete capability proof, safety
proof, and before/after snapshots. Block gitea_delete_branch and merged-cleanup
execution during audit phase, validate final reports for false no-mutations
claims, and document the boundary in the reconcile-landed-pr workflow.

gitea_mcp_server.py

@@ -546,6 +546,7 @@ import issue_work_duplicate_gate  # noqa: E402
 import merged_cleanup_reconcile  # noqa: E402
 import reconciler_profile  # noqa: E402
 import reconciliation_workflow  # noqa: E402
+import audit_reconciliation_mode  # noqa: E402
 import review_merge_state_machine  # noqa: E402
 import native_mcp_preference  # noqa: E402
 
@@ -3680,6 +3681,18 @@ def gitea_delete_branch(
             "permission_report": _permission_block_report("gitea.branch.delete"),
         }
 
+    audit_allowed, audit_reasons = (
+        audit_reconciliation_mode.check_audit_mutation_allowed("delete_branch")
+    )
+    if not audit_allowed:
+        return {
+            "success": False,
+            "performed": False,
+            "required_permission": "gitea.branch.delete",
+            "reasons": audit_reasons,
+            "audit_phase": audit_reconciliation_mode.current_phase(),
+        }
+
     verify_preflight_purity(remote)
     h, o, r = _resolve(remote, host, org, repo)
     auth = _auth(h)
@@ -3749,6 +3762,18 @@ def gitea_reconcile_merged_cleanups(
             "execute_confirmed must be True when dry_run=False (fail closed)"
         )
 
+    if not dry_run:
+        exec_allowed, exec_reasons = (
+            audit_reconciliation_mode.check_cleanup_execution_allowed()
+        )
+        if not exec_allowed:
+            return {
+                "success": False,
+                "performed": False,
+                "reasons": exec_reasons,
+                "audit_phase": audit_reconciliation_mode.current_phase(),
+            }
+
     h, o, r = _resolve(remote, host, org, repo)
     auth = _auth(h)
     base = repo_api_url(h, o, r)
@@ -3831,6 +3856,53 @@ def gitea_reconcile_merged_cleanups(
     return {"success": True, "performed": True, **report}
 
 
+@mcp.tool()
+def gitea_authorize_reconciliation_cleanup_phase(
+    operator_approved: bool = False,
+    workflow_authorized: bool = False,
+    delete_capability_proven: bool = False,
+    safe_to_delete_remote: bool = False,
+    safe_to_remove_worktree: bool = False,
+    before_state: str = "",
+    after_state: str = "",
+) -> dict:
+    """Authorize cleanup phase after audit-only reconciliation (#419).
+
+    Requires operator or workflow approval, exact delete_branch capability proof,
+    branch/worktree safety proof, and before/after state snapshots. Audit phase
+    forbids branch deletion, worktree removal, pushes, and issue/PR mutations.
+    """
+    delete_gate = _profile_operation_gate("gitea.branch.delete")
+    capability_ok = not bool(delete_gate)
+    if delete_capability_proven and delete_gate:
+        return {
+            "authorized": False,
+            "performed": False,
+            "delete_capability_verified": False,
+            "reasons": [
+                "delete_capability_proven=true but active profile lacks "
+                "gitea.branch.delete",
+            ] + delete_gate,
+            "audit_phase": audit_reconciliation_mode.current_phase(),
+        }
+    result = audit_reconciliation_mode.authorize_cleanup_phase(
+        operator_approved=operator_approved,
+        workflow_authorized=workflow_authorized,
+        delete_capability_proven=delete_capability_proven and capability_ok,
+        safety_proof={
+            "safe_to_delete_remote": safe_to_delete_remote,
+            "safe_to_remove_worktree": safe_to_remove_worktree,
+        },
+        before_after_snapshot={
+            "before": (before_state or "").strip(),
+            "after": (after_state or "").strip(),
+        },
+    )
+    result["performed"] = bool(result.get("authorized"))
+    result["delete_capability_verified"] = capability_ok
+    return result
+
+
 @mcp.tool()
 def gitea_assess_already_landed_reconciliation(
     pr_number: int,
@@ -6937,6 +7009,9 @@ def gitea_resolve_task_capability(
     if reason_msg:
         result["reason"] = reason_msg
     role_session_router.sync_route_from_capability(result)
+    if audit_reconciliation_mode.check_audit_task_enters_phase(task):
+        phase_record = audit_reconciliation_mode.enter_audit_phase(task)
+        result["reconciliation_phase"] = phase_record.get("phase")
     was_terminal = capability_stop_terminal.is_active()
     terminal = capability_stop_terminal.sync_from_capability_result(result)
     if terminal: