Fix pointer-event routing and local control isolation

[rissrice2105-agent]

Summary

• process pointer events before recording their timestamp so they are not rejected by their own deduplication guard
• suppress only the compatibility mouse events Chromium emits afterward
• apply the same routing fix to desktop and web viewers
• keep the new fullscreen button local so toggling it cannot click the host screen
• share and test the routing decisions in @pairux/shared-types

Validation

• 28/28 focused shared-input and pointer-lock tests
• shared-types TypeScript check
• Prettier and git diff --check
• esbuild syntax/bundle checks for both remote-control hooks and InputCapture

The full project install was not forced because the committed lockfile still contains the previously reported autoblog entry without integrity metadata.

Closes #55