Port confirmation fixes with browser and execution-boundary checks

When reusing card-layout fixes across MCP integrations, test the generated confirmation HTML rather than only CSS strings. A headless-browser matrix covering narrow/wide cards, floating-button lifts, and light/dark themes can also verify real argument hydration and edited-value postMessage events. Keep post-execution rendering failures separate from provider failures so a completed write is never reported as failed and retried. Redaction tests should verify that setting names such as COMPOSIO_API_KEY remain readable while actual assigned values are removed.