v0.42.20.0 fix: reliability wave — PGLite capture lock-pin + Postgres reconnect race + search embed-hang (#1762 #1745 #1775) (#1810)

* fix(core): drain fire-and-forget sinks before disconnect via a background-work registry (#1762)

New src/core/background-work.ts registry (Map<name,drainer>, ordered drain,
awaited abort). facts-queue (order 0, abort=shutdown), last-retrieved (1), and
eval-capture (3, now self-tracked) register as sinks. Both CLI exit paths
(op-dispatch finally + handleCliOnly finally) drain the registry before
engine.disconnect() so a PGLite db.close() can't race in-flight work into the
re-pump busy-loop that pinned the single-writer lock. Op-dispatch error path
converts process.exit(1) to exitCode+return so the finally still drains.

* fix(ai): bound every outbound AI call so a stalled provider can't hang (#1762/#1775)

withDefaultTimeout composes a per-touchpoint default deadline (chat 300s,
embed/multimodal 60s) with any caller signal via AbortSignal.any. Applied at the
SDK call layer (chat generateText, expand generateObject, OCR, per-sub-batch
embed) — covers native-anthropic + retries — plus per-request multimodal fetch.
embedQuery forwards abortSignal. Env: GBRAIN_AI_{CHAT,EMBED,MULTIMODAL}_TIMEOUT_MS.

* fix(postgres): module-mode reconnect preserves the shared singleton (#1745)

reconnect() branches on connection style. Module-singleton engines re-establish
idempotently via db.connect() (no-op when alive) + refresh the ConnectionManager
read pool, never db.disconnect() — so a transient blip no longer nulls the shared
sql out from under concurrent ops (which threw 'connect() has not been called').
Fail-loud on real connect failure. Instance pools keep teardown+recreate.

* fix(search): bound the query-time embed so a stall falls back to keyword (#1775)

search/query default to cheap-hybrid (embeds the query); a stalled provider made
the embed never settle, so the keyword fallback never engaged and the command
force-exited with no output. One shared QueryEmbedDeadline (6s, floored 2s per
embed) covers both the cache-lookup and inner embeds via embedQueryBounded
(abortSignal + Promise.race) → existing keyword fallback engages. Also registers
the search-cache background-work drainer (now bounded). Env: GBRAIN_QUERY_EMBED_TIMEOUT_MS.

* test+chore: reliability wave tests + v0.42.11.0 (#1762 #1745 #1775)

New: background-work registry unit, query-embed deadline unit, eval-capture
drain unit, postgres reconnect E2E (#1745), gbrain capture exit-clean case in
the PGLite serial test. Updated fix-wave-structural assertions to the registry
shape. VERSION/package.json/CHANGELOG -> 0.42.11.0; TODOS retrofit marked done.

Incorporates + hardens PR #1763 (drain-before-disconnect + embed fetch timeout);
the residual hung-Haiku hole is closed by the facts shutdown() abort belt.

Co-Authored-By: ElliotDrel <noreply@github.com>
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

* docs: document background-work registry + v0.42.11.0 reliability wave in CLAUDE.md (regen llms)

* chore: bump release version 0.42.11.0 -> 0.42.20.0

Rename the reliability-wave release version per request. Trio
(VERSION / package.json / CHANGELOG) reconciled; in-code version-tag
comments and test fixtures updated; llms regenerated.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: ElliotDrel <noreply@github.com>
Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

VERSION

@@ -1 +1 @@
-0.42.19.0
+0.42.20.0