[Connector Hub Phase 1] Catalog UI + Obsidian smoke test

[kovtcharov]

Parent: #735 (Connector Hub)

Phase 1 — demoable in 1 week, zero dependencies.

Scope

Prove the end-to-end path: catalog → connect → tools appear in agent — using Obsidian (no secrets, stdio transport, zero auth).

Deliverables

Backend

• src/gaia/ui/connectors/__init__.py — package marker
• src/gaia/ui/connectors/schema.py — ConnectorManifest, AuthField, ConnectionState pydantic models
• src/gaia/ui/connectors/catalog.py — curated catalog (start with Obsidian, Filesystem, Playwright from existing routers/mcp.py)
• src/gaia/ui/routers/connectors.py — GET /api/connectors/catalog, POST /api/connectors/{name}/connect, POST /api/connectors/{name}/test
• Register router in src/gaia/ui/server.py

Frontend

• IntegrationsPage.tsx — route at /integrations, renders catalog grid
• ConnectorCard.tsx — tile with name, icon, description, connection state badge, Connect button
• Wire into app router + add nav entry
• Basic "Connect" action that calls /api/connectors/{name}/connect and shows tool count on success

Validation

• Connect Obsidian in the Agent UI, ask ChatAgent "list my daily notes", see real vault content
• GET /api/connectors/catalog returns at least 3 entries with correct schema

What this does NOT include

• No secrets/vault (Phase 2, needs ServiceIntegrationMixin: API discovery, credential management, and preference learning #545)
• No OAuth (Phase 3)
• No per-agent enablement UI (Phase 2)
• No CLI commands (Phase 4)

Plan reference

docs/plans/connector-hub.mdx §9 Phase 1