OpenCode 1.4.0 moved `UserMessage.variant` from the top-level to
`UserMessage.model.variant`. OpenChamber still read the legacy location,
so variant selection silently stopped being restored on sessions served
by OpenCode 1.4.0+.
Read `model.variant` first and fall back to the legacy top-level field
so both pre-1.4 and 1.4+ OpenCode servers keep working.
OpenCode v1.3.13 may omit cost and capabilities from provider model
config responses. The deriveModelMetadata function accessed these
fields without optional chaining, causing a TypeError that crashes
the chat interface.
Reduce layout thrashing during virtual keyboard open/close on mobile by
batching resize and visualViewport event handlers to once per animation
frame. No visual or behavioral changes — desktop is unaffected.
- MainLayout: rAF-batch visualViewport resize/scroll and window resize
listeners (was firing 10-20x per frame during keyboard animation)
- Header: rAF-batch ResizeObserver and resize/orientationchange callbacks
- ChatContainer: rAF-batch ResizeObserver and resize fallback callbacks
- useDeviceInfo: 150ms debounce on resize listener (device type does not
change during keyboard transitions)
Gyumin Lee