- Add preview embed diagnostics with richer error classification and fallback state handling
- Improve PreviewIframe and DevServerView retry UX for timeout and iframe failure states
- Adjust preview layout/styles to prevent clipping and header overflow while keeping fallback panels centered
- Expand dashboard tests to cover fallback transitions, retry flows, and responsive CSS behavior
- Add usePreviewEmbed hook to derive preview embed URLs and availability state
- Add PreviewIframe component with iframe load/error wiring and deduplicated error callbacks
- Integrate preview panel actions, fallback messaging, and embedded iframe rendering in DevServerView
- Expand test coverage for usePreviewEmbed, PreviewIframe, and DevServerView preview integration scenarios
