Add a live data layer: merge changed rows by id instead of reloading lists

[HomemadeToast57]

Does what 0.2.0-next.20 concluded was the real fix for rows popping out and back in:

Both are the same underlying thing — any design that replaces the whole list from a server snapshot has a window in which that snapshot is stale. The fix is to stop replacing the list (merge the changed row by id), not to keep shrinking the window.

next.19 shrank the window (reload-hold) and was reverted. This stops replacing the list.

What's new

LiveEntityStore (src/live.ts) is the sync state machine; useEntity (bool-sdk/react) is its React surface:

const todos = useEntity("todos", { sort: "-created_at" });
todos.data; todos.loading; todos.error;
await todos.create({ title });           // optimistic, rolls back on failure
await todos.update(id, { done: true });
await todos.remove(id);

One call replaces the useEffect + useState + load() + subscription pattern the system prompt taught every app to hand-wire.

The four defects it fixes

	Before	After
Stale snapshot overwrites screen	full list replaced on every ping	deltas merged by id — no snapshot to be stale
Bulk write cost	trigger is FOR EACH ROW → 50 rows = 50 full reloads	pings batch into ONE keyed fetch per 50ms
Out-of-order responses	last-to-land wins, view rewinds	monotonic sequence, stale responses dropped
Optimistic rows	wiped by a concurrent reload	overlay on committed state; rollback drops overlay

Reconcile cost

• DELETE → applied locally, zero fetches
• ding carries row (future private-channel doorbell) → zero fetches
• otherwise → fetch only the changed rows by id, through the gateway so auth + telemetry still apply
• ding with no id (older platform trigger) → one coalesced full reload

Filtered views self-maintain: matchesFilter evaluates the same DSL entities.ts translates to PostgREST, including SQL three-valued null semantics, so a delta-applied row matches what the next full load would return.

Testing

bun test — 134 pass, 0 fail. bun run typecheck clean. 24 new tests in src/live.test.ts cover coalescing, delete-without-fetch, row-on-ding, RLS-hidden rows leaving the view, filter transitions, stale-response dropping (via a gated deferred), optimistic survival across a concurrent refetch, rollback on every mutation, and self-echo dedupe.

Paired with

Platform PR restoring id to the doorbell payload and adding the capability-gated prompt variant.

🤖 Generated with Claude Code