Previously SSR rendered at step 16 (hardcoded) but client initialized
from cookie, causing a flash from 16 to the cookie value on return visits.
Fix: Both SSR and client default to step 0. The def-store initializer
reads the cookie for the client's initial value. Return visits show
a progressive fill (0 → cookie value) instead of a jarring state jump.
- step-idx default: (signal 0) in both SSR and client paths
- def-store: reads sx-home-stepper cookie for initial value, defaults to 0
- Removed redundant post-hydration cookie reset block
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
giles
3b06299e4b