- `bsk session start --width <px> --height <px>` opens the Agent Window
with the given outer size (chrome.windows.create)
- new `bsk window resize --session <id> --width <px> --height <px>`
resizes the Agent Window at runtime (chrome.windows.update)
- both validated on CLI, daemon and extension sides (100..=7680 CSS px)
- protocol: new tool.window_resize method (BrowserMutation) and
optional width/height on tool.session_start params; schemas regenerated