feat(engine): the wiring wave — stamps ride every flush, provider generations, waitForIndexed, adopt-backfill, match-all serves

- Watermark stamping fans out at flush: all three projections stamped
  with the committed generation before their flushes persist.
- waitForIndexed(path?, {generation, timeoutMs}) — the one honest read
  barrier for write-then-recall consumers; typed timeout error carries
  the pending count and names the gauge; getIndexStatus() gains
  per-projection gauges. awaitPendingEmbeds() unchanged underneath.
- adoptLogAuthority() self-backfills curable divergences (pre-log
  records, witness drift) by identity re-commit before flipping — a
  fresh brain flips clean; log-ahead divergences still refuse loudly.
- The verification oracle gains VERB legs (all four divergence classes;
  unwired = honest verbsChecked: 0, never a scope claim).
- find({where: {}}) match-all serves (was silent-empty, warm AND cold;
  same fix in count/streaming/subgraph seeding); removeMany({where:{}})
  refuses typed — a match-all bulk delete must be explicit.
- Aggregation native envelope stamped via noteSourceGeneration before
  serializeState; the native-blob restore gates through the same
  adoption verdict as caller-side state (the unconditional adopt dies).
- LC8 pinned: a wholesale directory move opens and serves identically
  across all three intelligences, with history traveling.

Gates: unit 2031/2031 (156 files) · integration 812 (91 files) ·
conformance 27/27.

src/index.ts

@@ -83,6 +83,14 @@ export type {
   AggregationProvider
 } from './types/brainy.types.js'
 
+// Read-barrier contract (waitForIndexed): the leg names, the options, and
+// the typed timeout error (a value export — consumers catch it by instanceof)
+export type {
+  IndexedProjectionPath,
+  WaitForIndexedOptions
+} from './types/brainy.types.js'
+export { WaitForIndexedTimeoutError } from './types/brainy.types.js'
+
 // Reserved-field contract — the canonical list of Brainy-owned field names
 // that may never appear inside a `metadata` bag (see docs/concepts/consistency-model.md)
 export {