Send Droid screenshots as attachment paths over worker IPC

[arul28]

Summary

• Droid forked-worker screenshot IPC now sends { path, mimeType, rootPath } instead of inlined base64 on child.send, matching Cursor and Pi.
• The worker re-opens the attachment through readFileWithinRootSecure (10 MB cap). Remote image URLs become prompt text because Droid's stream API has no URL image form.
• Follow-up to Fix Cursor hook.sock recycle and forked-worker screenshot IPC #1177, which left Droid on the stalling inline-bytes path.

Test plan

• droidSdkPool.test.ts asserts send payloads carry paths, not data
• agentChatService.test.ts sendMessage with a PNG attachment does not inline PNG magic bytes
• Desktop typecheck on the prior tree; protocol/pool/image unit tests green after the unused type-guard drop

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Note

Medium Risk
Changes how user images reach Droid across process boundaries; wrong path/sandbox reads would break vision turns but avoids IPC stalls from large payloads.

Overview
Droid chat turns no longer inline screenshot base64 on the worker JSON pipe. Main process now builds prompts with the same path-only attachment shape as Pi (buildPathOnlyWorkerPrompt / buildDroidWorkerPrompt): text without embedded image bytes, plus { path, mimeType, rootPath } for on-disk attachments. The Droid worker materializes those paths locally via materializeWorkerImages before calling @factory/droid-sdk.

DroidSdkUserImage is updated to document and type path refs (with optional tiny inline data for tests). Pool and integration tests assert IPC carries paths, not data, and orchestration tests use vi.waitFor where awaitDispatch resolves before sendPrompt. Docs note Pi/Droid URL images become prompt text, not IPC URLs.

^{Reviewed by Cursor Bugbot for commit 71dd320. Configure here.}

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1 Skipped Deployment

Project	Deployment	Actions	Updated (UTC)
ade	Ignored	Preview	Aug 29, 2026 8:08am

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📥 Commits

Reviewing files that changed from the base of the PR and between 714e3c3 and 0e00a0e.

⛔ Files ignored due to path filters (2)

• docs/features/chat/README.md is excluded by !docs/**
• docs/features/chat/agent-routing.md is excluded by !docs/**

📒 Files selected for processing (6)

• apps/desktop/src/main/services/chat/agentChatService.test.ts
• apps/desktop/src/main/services/chat/agentChatService.ts
• apps/desktop/src/main/services/chat/droidSdkPool.test.ts
• apps/desktop/src/main/services/chat/droidSdkProtocol.ts
• apps/desktop/src/main/services/chat/droidSdkWorker.ts
• apps/desktop/src/main/services/chat/workerAttachmentImages.ts

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