chore(release): agent-knowledge 1.9.0 — real web-research worker + live A/B

[drewstone]

Bumps @tangle-network/agent-knowledge 1.8.0 → 1.9.0.

npm is at 1.8.0 but origin/main has #32 unshipped — the real web-research worker (createWebResearchWorker + createVerifyingResearchDriver + createTangleRouterClient, src/web-research-worker.ts) plus the genuinely-live A/B arm. That's a new consumable research backend, so it warrants a minor release.

Version-only change. Local gates green on this branch:

• typecheck: 0 errors
• lint: 0 errors (2 pre-existing warnings, unrelated)
• build (tsup): success — dist/index.js + dist/index.d.ts export createWebResearchWorker
• test (vitest): 131 passed / 7 skipped (live + 1 expensive)

Publish is OIDC tokenless via publish.yml on a v* tag push (same as v1.8.0/v1.7.0). Tag pushed after squash-merge.

[tangletools]

✅ Auto-approved PR — d30738a0

Blanket team auto-approval is enabled for this reviewer service.
The full PR reviewer audit still runs separately and will publish findings if it detects issues.

_{tangletools · auto-approval · reason: blanket_auto_approve · 2026-06-24T22:26:01Z}