TPP: replace the cycling seed button with a…

Details

The optimizer seed was a single button that only cycled 0→…→29→0, so
reaching a specific seed meant many clicks and there was no way to jump to
one. Replace it with a proper stepper: − and + that step (clamped to 0–29,
no wrap, disabled at the ends) plus a number field you can type into.
- v3tppwSetSeed() clamps any value to [0, 29]; typed entry commits on
  change/Enter, out-of-range clamps, non-numeric reverts to the current
  seed. In the coverage phase a change re-runs the live fit; the choice
  still persists (localStorage).
- v3tppwSync() drives the field value and the +/- disabled states, and
  won't overwrite the field while it is focused mid-type.
- The card's ←/→ and [ ] { } shortcuts now ignore keydowns originating in
  the seed field, so typing/arrowing there no longer steps the phase.
Verified headless: 15/15 stepper checks (clamp both ends, no wrap,
typed-entry clamp/revert, keyboard-guard, phase-3 refit, persistence);
Reset (#66) still restores seed->0 (18/18); 16/16 core tests; tsc clean.
Stacks on #66 (adds the shared files' nearby edits on top of the Reset
button) to keep the two changes conflict-free.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_014c7dbCGbQxtWedKRSx4sJi

Files changed (3)