feat: compose AgentWidget AI frontdesk

[guoweichen-ai]

What

• replace the starter welcome/session shell with an AgentWidget AI frontdesk composed over the existing SessionProvider and one LiveKit Room
• consume the provider-neutral React SDK plus LexVoice adapter from lexmount/agent-uilib#2
• add authenticated spawn and isolated SSE surface routes so Codex, MCP, or another host can publish UI without starting a voice session
• preserve and harden real-device startup: browser preview defaults, audio unlock in the click gesture, LiveKit reconnect, and server-input dispatch ordering

Why

Reusable UI and provider adapters belong in agent-uilib; this repository should own the deployable AI frontdesk product and LexVoice session composition. The adapter wraps the existing room instead of creating a second connection.

Impact

• requires agent-uilib PR feat: update ui #2 first; the dependency is pinned to commit 996976ea8c4a2de515943a6d5138e385c6f6cd50 for Draft review
• configure AGENTWIDGET_HOST_TOKEN and use the same high-entropy channel in the host header and browser query
• surface delivery is process-local for now, so /api/agentwidget/* needs one Next.js instance or sticky routing until shared pub/sub is added

Checks

• pnpm install --frozen-lockfile
• pnpm test (249 passed)
• pnpm lint
• pnpm format:check
• pnpm build
• production E2E: POST deterministic person event -> authenticated spawn -> channel/SSE -> styled Person Context surface in the browser, including idle-session rendering

Draft dependency note

GitHub Actions currently stops during install because agent-uilib is private and this repository has no cross-repository read credential. Before merge, either publish @lexmount/agentwidget-sdk or add a scoped read-only repository secret/token for CI. No credential is embedded in this branch.

[guoweichen-ai]

Superseded by lexmount/super-webapp#3. agent-starter-react remains a starter/template; the LexVoice AgentWidget product frontend now lives in super-webapp.