Release v0.2.5 default-app reliability hotfix

[terrorproforma]

What changed

• Keep Explore Better as the Windows folder and drive default while launching the installed desktop executable directly, without the PowerShell launcher flash.
• Carry the preview digest and one-use apply token through quick Paste and Send To operations.
• Add packaged integration and real browser regression coverage for both fixes.
• Harden acceptance clients around Windows reserved ports, MCP stale revisions, Inspector heartbeats, and cache timing noise.
• Publish the v0.2.5 website copy while preserving the v0.2.4 homepage as legacy-2026-07-20.html.

Root cause

Packaged integration generation could retain an older browser-window launch preference and route shell opens through the generated PowerShell launcher. Quick transfer paths planned correctly but discarded the plan digest and apply token before the mutation request.

User impact

Folder and drive opens continue to use Explore Better as the default without a terminal popup, and Paste/Send To complete through the existing preview-before-apply security boundary.

Validation

• Full acceptance profile: 131 pass, 0 fail.
• Default Explorer UI: 15/15.
• Current-user shell integration: 12/12.
• Dual-pane transfer safety: 19/19.
• Security boundary: 11/11.
• MCP UI matrix: 43/43 views.
• Release readiness: 31/31.
• Installer SHA-256: 64829c4a35e8693cd991a47709fc178b589a35719851f3f88bb77495f8a0c88c.
• Installed app.asar matched the verified build and a real Windows folder shell-open produced the Explore Better main window.