Replaces three race-prone seeding paths in `workbench-scenes.svelte.ts`
(count==0 init seed, replay-on-register seed, per-Space-change seed)
with a single registry pattern:
- `data/scope/per-space-seeds.ts` — registry of `Seeder` callbacks,
fired by `setActiveSpace` whenever the active Space id changes.
Errors are isolated per seeder so one module's bug can't block the
others.
- `data/seeds/workbench-home.ts` — registers the workbench Home seeder.
Uses the deterministic id `seed-home-${spaceId}` and a get-then-add
guard, making the seed structurally idempotent: re-running for the
same Space is a no-op regardless of timing. Replaces the old
random-UUID + check-by-presence pattern that the seeding race could
defeat.
- `data/seeds/index.ts` — side-effect barrel imported once at the top
of `(app)/+layout.svelte` so every module's seeder is in the
registry before the first `loadActiveSpace` fires.
- `active-space.svelte.ts` — both `setActiveSpace` and `loadActiveSpace`
funnel through a private `applyActiveSpace` helper that calls
`notifyHandlers` AND `runSpaceSeeds` in one place. No more divergent
state-update paths.
- `workbench-scenes.svelte.ts` — `ensureSeedScene` and the two
ad-hoc seed calls deleted. The store now only owns rendering and
user-driven CRUD; seeding lives in the registry.
This is Schicht B + C of the broader cleanup plan
(docs/plans/workbench-seeding-cleanup.md). Schicht D-soft already
collapsed existing duplicates; this PR prevents new ones from forming.
The tests cover the registry contract (register/run/idempotency/error
isolation), the deterministic-id helper, and the seeder against an
isolated Dexie fixture (race-safety, no-overwrite of customised rows,
per-Space isolation).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
