fix(desktop): allow preview automation in agent-created threads - #8483

💭 I'm reviewing the diff, which adds a Desktop-specific schema with a longer tabId limit, and checking the contracts file alongside the test file for correctness—particularly whether the import style and the PreviewManager.PreviewManager.of usage follow conventions. Since this is a genuine behavior change to the schema limit, adding tests here makes sense rather than being unnecessary scaffolding, so I want to look at the actual files to confirm the details.

1. browse_code — packages/contracts/src/ipc.ts

2. browse_code — apps/desktop/src/ipc/methods/preview.test.ts

💭 Let me check the PreviewAutomationStatus definition in contracts.

3. git_tools — PreviewAutomationStatus

💭 This looks like a schema/type change rather than an Effect service refactor, so the usual service-definition conventions mostly don't apply here. Scanning the diff, I don't see any Layer.succeed, ManagedRuntime, or runPromise usage, and the imports and test setup with PreviewManager's Service type look correct. The one thing to verify is whether the focused tests are justified given this is a real behavior change, and I want to check PreviewAutomationHosts.tsx next. The status field type changed from PreviewAutomationStatus to DesktopPreviewAutomationStatus in the bridge, but since both resolve to string-or-null at the type level without branding differences, this should type-check fine and isn't a convention violation. I also want to check whether DesktopPreviewAutomationStatusSchema needs an explicit Codec annotation like its neighbors, but since other similar exports skip it too, that's consistent. The placement between the other Desktop schemas looks fine, and the fields spread intentionally drops the tabId max length constraint. Now I want to check previewAutomation.ts to see how tabId is schema'd there.

4. browse_code — packages/contracts/src/previewAutomation.ts

💭 This is schema-only with no convention violations found. There's a slight conflict between the instruction to output exactly "All clear" and the requirement for valid JSON output, so I'll resolve it by setting the JSON fields (state, title, summary) to reflect "All clear" while keeping the response properly structured.