• nilnil (4 → 0): added nolint:nilnil to intentional nil, nil returns in test mocks (MockProvider.CreateInterceptor, mockServerProxier.CallTool) and lastUserPrompt (no user prompt found is not an error)
• gocritic FullResponseWriter (1 → 0): added Hijack() method to statusCapturingWriter delegating to underlying http.Hijacker
• revive defer-in-loop (1 → 0): replaced defer shutdownCancel() with explicit shutdownCancel() call after events.Shutdown
• staticcheck SA1026 (1 → 0): replaced responses.Error (which embeds *http.Request with unmarshalable GetBody func) with a plain struct matching the same JSON shape

All lint errors are now resolved — 0 remaining.