The seed-defaults effect fired whenever fontA/fontB were still
undefined, including the window between constructor reading storage
and the per-id batch resolving. On a slow batch or fast catalog the
effect clobbered storage with catalog[0]/catalog[N-1], losing the
user's pick on reload.
Now bails when storage already holds IDs, and reads storage via
untrack so per-font selection writes don't re-trigger the effect.
Adds a deterministic regression test that controls catalog/batch
ordering via mockImplementation timing.
Ilia Mashkov
b9e21a66d3