feat(studio): ProbeScript recorder

[pbertsch]

Summary

• ● Record button in the Studio toolbar — starts/stops an interactive recording session
• Calls probe.start_recording / probe.stop_recording on the connected agent (WebSocket connections only — simulators and emulators)
• Agent streams probe.recorded_event notifications; Studio converts each to a ProbeScript step and appends it to the editor in real time (with >2s gap → automatic wait N seconds steps)
• ⌘⇧R keyboard shortcut to toggle recording
• Red pulsing ■ button while recording; reverts to ● Record on stop
• On stop: StopRecording() returns the full assembled ProbeScript, reconciling the live preview
• Note: Physical-device (HTTP) connections return an error; recording requires WebSocket (WS is used by default for simulators/emulators)

Test plan

• go build ./... passes
• Frontend builds: npm run build passes in studio/frontend/
• Connect to iOS simulator → Record button enabled
• Click Record → button turns red/pulsing, editor shows header
• Interact with app → steps appear live in editor
• Click Stop → final assembled script replaces editor content
• ⌘⇧R starts/stops recording
• Attempting to record on physical device (HTTP) shows actionable error toast