feat(restart): audit lifecycle events and durable incidents (#665)

Add restart_audit with mcp.restart.* event schema, redacted emission via
gitea_audit, correlation ids, and incident materialization for failed drain
and break-glass. Wire gitea_request_mcp_restart to always audit impact
previews and fail closed on privileged apply when the audit sink is enabled
but write fails.

Closes #665

gitea_mcp_server.py

@@ -2069,6 +2069,7 @@ import lease_policy  # noqa: E402
 import workflow_dashboard  # noqa: E402  # #605 live queue/lease dashboard
 import restart_coordinator  # noqa: E402  # #658 MCP restart coordinator/impact
 import drain_proof  # noqa: E402  # #661 pre-restart drain proof and hard gate
+import restart_audit  # noqa: E402  # #665 restart audit events + incidents
 import incident_bridge  # noqa: E402
 import sentry_observability  # noqa: E402  (#606 optional Sentry observability)
 import sentry_incident_bridge  # noqa: E402  (#607 Sentry→Gitea incident bridge)
@@ -22750,6 +22751,38 @@ def gitea_request_mcp_restart(
     # and a durable incident is raised. Break-glass is the only bypass and its
     # authorization is read from the environment, never self-asserted.
     payload["apply_supported"] = False
+    # #665: correlation id threads impact preview → apply gate → incidents.
+    correlation_id = restart_audit.new_correlation_id()
+    payload["correlation_id"] = correlation_id
+    auth_user = None
+    try:
+        # remote-only: host override is for operator diagnostics, not required here
+        auth_user = (gitea_whoami(remote=remote) or {}).get("username")
+    except Exception:  # noqa: BLE001 — identity is best-effort for audit
+        auth_user = None
+    preview_audit = restart_audit.record_restart_lifecycle(
+        event_type=restart_audit.EVENT_IMPACT_PREVIEW,
+        outcome=str(report.verdict or "unknown"),
+        correlation_id=correlation_id,
+        remote=remote,
+        org=o,
+        repo=r,
+        requesting_session_id=sid,
+        restart_class=restart_class,
+        profile_name=profile_name,
+        authenticated_username=auth_user,
+        reasons=list(report.reasons or []),
+        details={
+            "dry_run": True,
+            "allow_restart": bool(report.allow_restart),
+            "inventory_complete": inventory_complete,
+        },
+        privileged=False,
+    )
+    payload["restart_audit"] = {
+        "correlation_id": correlation_id,
+        "impact_preview_written": preview_audit["audit_written"],
+    }
     if not dry_run:
         proof_obj: dict | None = None
         proof_parse_error: str | None = None
@@ -22809,6 +22842,86 @@ def gitea_request_mcp_restart(
         )
         if not gate.allow and gate.incident is not None:
             payload["incident"] = gate.incident
+
+        # #665: audit apply-gate + materialize durable incidents for failed
+        # drain and break-glass. Privileged apply denies if audit is enabled
+        # and the sink write fails.
+        incident_desc = restart_audit.incident_from_apply_gate(
+            gate_payload={
+                **gate_payload,
+                "incident": gate.incident,
+                "allow": gate.allow,
+            },
+            break_glass=break_glass,
+            correlation_id=correlation_id,
+            requesting_session_id=sid,
+            restart_class=restart_class,
+            remote=remote,
+            org=o,
+            repo=r,
+        )
+        if incident_desc is not None:
+            payload["incident"] = incident_desc
+
+        def _create_restart_incident_issue(
+            *, title, body, labels, org=None, repo=None, **_kw
+        ):
+            return gitea_create_issue(
+                title=title,
+                body=body,
+                labels=labels,
+                remote=remote,
+                host=h,
+                org=org or o,
+                repo=repo or r,
+            )
+
+        apply_audit = restart_audit.record_restart_lifecycle(
+            event_type=(
+                restart_audit.EVENT_BREAK_GLASS
+                if break_glass
+                else restart_audit.EVENT_APPLY_GATE
+            ),
+            outcome=(
+                "break_glass"
+                if break_glass
+                else ("allow" if payload["apply_authorized"] else "deny")
+            ),
+            correlation_id=correlation_id,
+            remote=remote,
+            org=o,
+            repo=r,
+            requesting_session_id=sid,
+            restart_class=restart_class,
+            profile_name=profile_name,
+            authenticated_username=auth_user,
+            reasons=list(gate_payload.get("reasons") or []),
+            details={
+                "apply_authorized": payload["apply_authorized"],
+                "drain_gate_allow": gate_payload.get("drain_gate_allow"),
+                "restart_class_authorized": restart_class_authorized,
+                "break_glass": break_glass,
+                "proof_id": gate_payload.get("proof_id"),
+            },
+            privileged=True,
+            create_incident=incident_desc,
+            create_issue_fn=_create_restart_incident_issue
+            if incident_desc is not None
+            else None,
+            dry_run_incident=False,
+        )
+        payload["restart_audit"] = {
+            "correlation_id": correlation_id,
+            "impact_preview_written": preview_audit["audit_written"],
+            "apply_gate_written": apply_audit["audit_written"],
+            "incident_result": apply_audit.get("incident_result"),
+        }
+        if apply_audit["deny_reasons"]:
+            payload["apply_authorized"] = False
+            payload["reasons"] = list(payload.get("reasons") or []) + list(
+                apply_audit["deny_reasons"]
+            )
+            payload["success"] = True
     return payload