feat(dashboard): FollowerConfigEditor UI — mirrors SafetyLimitsEditor pattern

Adds schema-driven editor for Follower.General and Follower.FollowerOverrides
config, providing the same UX as the Safety section override editor:

- FollowerConfigEditor.js: Full editor with General defaults view,
  per-follower override selector, add/remove properties, enum/boolean/
  number types with sliders, comparison with General values
- followerConfigSchemaUtils.js: Static schema metadata for all 12
  General params across 5 categories (timing, smoothing, target_loss,
  guidance, altitude) — re-exports KNOWN_FOLLOWERS from safetySchemaUtils
- SectionEditor.js: Routes Follower section's General and
  FollowerOverrides params to FollowerConfigEditor, disambiguates from
  Safety section's FollowerOverrides using configValues keys, forces
  card layout for Follower section

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: alireza787b