feat: add chat & search adapters

[kantorcodes]

Summary

• Adds a first-class adapter pattern to agent0-sdk for agent discovery (search/vector search) and agent communication (chat), so teams can plug in different backends behind a stable SDK
  API.
• Provides an optional Registry + Broker adapter package under agent0-sdk/registry-broker (powered by @hol-org/rb-client) for ERC‑8004 discovery + broker-managed UAID chat sessions.
• Includes a runnable example (agent0-ts/examples/broker-chat.ts) and an integration test (agent0-ts/tests/registry-broker-erc8004.test.ts) exercising the adapter integration end-to-end.

Value

• Improves DX: register adapters once, then call sdk.search(...), sdk.vectorSearch(...), and sdk.chat(...) consistently (with optional explicit adapter IDs when multiple are registered).
• Keeps the SDK extensible: projects can use the provided Registry + Broker adapters or implement their own adapters for other registries/brokers.

How to try

• Demo: REGISTRY_BROKER_API_KEY=... npx tsx examples/broker-chat.ts (defaults to https://hol.org/registry/api/v1)
• Tests: REGISTRY_BROKER_BASE_URL=... npm test -- --testPathPattern=registry-broker (set ERC8004_AGENT_UAID=... to enable the live chat test)

[rickycambrian]

@kantorcodes worked for me but not right off the bat, left some notes here on some points, but it did work for me ✅
PR_fixes.md

Intuitively I feel like there should be a more decentralized and direct way to do this that doesn't require a broker in between, but also think options are always good to have

[kantorcodes]

@kantorcodes worked for me but not right off the bat, left some notes here on some points, but it did work for me ✅ PR_fixes.md

Intuitively I feel like there should be a more decentralized and direct way to do this that doesn't require a broker in between, but also think options are always good to have

Thanks for reviewing this work. Should be good for another pass.

[rickycambrian]

@kantorcodes all looks good to me 👍