project.generate() crashes on incomplete API response — missing defensive null checks

[saintwknd]

project.generate() intermittently throws Cannot read properties of undefined (reading 'screens') when the API returns an incomplete response. The screen IS successfully created on Stitch (visible in the dashboard at stitch.withgoogle.com/projects), but the SDK fails to parse the response.

Root cause (project.js line 29):

return new Screen(this.client, {
...raw.outputComponents[0].design.screens[0], // no null checks
projectId: this.projectId
});

screen.variants() already handles this correctly with optional chaining:

((raw.outputComponents || []).flatMap((a) => a?.design?.screens || []) || [])

generate() and edit() should use the same defensive pattern.

Environment: @google/stitch-sdk v0.0.3, model GEMINI_3_FLASH