fix(browser): keep new markers out of find and time out a hung name claim

[waleedlatif1]

Summary

• Follow-up to feat(browser): sharper computer use for the desktop browser agent #8283, whose last commit did not land with the merge
• browser_find collects its outline without new markers, so a search for "new" (or "New issue") no longer matches every recently added element, and a find no longer consumes the markers the next snapshot should show
• A snapshot element counts as shown only once its line is actually emitted
• The download name claim (the empty O_EXCL placeholder) runs inside the 5 s allocation timeout, so a hung filesystem stops the download instead of leaving it paused with its name reserved; a placeholder written after the timeout is removed
• After a successful move the download record no longer points at the finished file as a placeholder
• An already-aborted click sends no input at all, including the pointer move

Type of Change

• Bug fix

Testing

• 1,912 desktop tests pass; the 7 new or updated tests fail against staging's sources and pass with this change
• Desktop type-check, lint, block registry, check:audits, and docs manifest pass
• Tool catalog regenerated from mothership staging is unchanged, so no mothership counterpart is needed

Checklist

• Code follows project style guidelines
• Self-reviewed my changes
• Tests added/updated and passing
• No new warnings introduced
• I confirm that I have read and agree to the terms outlined in the Contributor License Agreement (CLA)

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1 Skipped Deployment

Project	Deployment	Actions	Updated
docs	Skipped		Sep 25, 2026 2:25am UTC

[cubic-dev-ai]

No issues found across 8 files

Confidence score: 5/5

• Automated review surfaced no issues in the provided summaries.
• No files require special attention.

_{Re-trigger cubic}

[greptile-apps]

Confidence Score: 5/5

[Medium risk] Adjusts browser automation snapshot capture and download handling.

The PR appears safe to merge; no actionable issue was identified.

Summary

This PR keeps new markers out of browser-find reads, puts download name claims within the allocation timeout, clears the placeholder reference after a successful move, and prevents input from an already-aborted click.

_{Reviews (1) · Last reviewed commit: "fix(browser): keep new markers out of fi..."}