fix(computer): smooth native drag trajectory

[quanru]

Summary

• reproduce the Linux/VNC-style drag failure with a real Chromium window on Xvfb
• move the held pointer through intermediate coordinates so native drag state machines can observe the active drag before release
• add unit coverage for input ordering and a focused hosted-Linux regression job that needs no model credentials

Root cause

The computer driver moved from source to target in one native pointer jump. Desktop drag-and-drop state machines use the first movement beyond their threshold to activate dragging, so the target needs a later held-button movement before mouseup. With only one jump, the source entered drag mode but the target never observed it.

GitHub Actions reproduction

• Before (same stabilized fixture, legacy one-jump implementation): failed
• After (20-step held-pointer trajectory): passed

Validation

• pnpm run lint
• npx nx test @midscene/computer
• npx nx build @midscene/computer
• AI_TEST_TYPE=computer npx nx test @midscene/computer -- tests/ai/linux-drag-and-drop.test.ts --retry 0 (skipped locally on macOS; passed in the hosted Linux run above)

[chatgpt-codex-connector]

Codex Review Summary

This comment shows the latest Codex review activity on this pull request.

Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-09-04T04:03:25.115963Z	c164258	PR opened

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