feat(launcher): the pet in the header reacts to what you type - #71

What this does

The pet in the corner of the launcher was a still picture. Now it reacts.

How

• The sprite is not redrawn. cat-preview.js is shared with the site and tests/site-sync.test.js keeps the copies identical, so the finished picture is moved instead. Breathing animates scale, a mood is a rotate pose, a one-off is translate. They are separate CSS properties, so they compose, and all of it stays on the compositor.
• src/launcher-pet.js is a pure function from (query, rows, idle time) to a mood. It sees whether a row can be run, never its wording, which keeps the launcher's rule that nothing is decided by reading a title.
• It holds still under prefers-reduced-motion and under the app's own setting. The pose stays; every animation and transition goes.

Found in review, fixed before this was pushed

• A long sentence followed by Escape dozed at once, because Escape empties the box without an input event.
• One animation-duration on the doze rule outranked the hop and stretched it to six seconds. The breathing speed is now a variable.
• The launcher re-renders once a second while a timer row counts down, and that cut a hop short. A reaction now ends with its own animation.
• Reopening the launcher could show the last mood for a moment.

Limits

• The eyes do not close for the doze and do not track the text. Both need the sprite itself to change, in src/ and site/ together. The lean stands in for eye tracking.
• Pixel art rotated a few degrees is slightly jagged. Worth a look at real size before merging.

Test plan

• npm test: 520 pass, 0 fail, 4 skipped (POSIX only)
• npx eslint . clean
• The real launcher page driven through twelve steps in a throwaway Electron window, reading the mood attribute, the running animations and the computed pose at each: matches the table. Run again with the app's hold-still setting: no animation at any step, poses kept.
• Screenshots of the tilt and the doze
• Watch it in the running app. The harness reads state; nobody has yet watched the motion at real speed.
• Not run on macOS