ChatGPT plugin, step 2: inline UI cards via MCP Apps (document list and document preview)

Summary Add inline UI cards to the Outline MCP server using the open MCP Apps standard, so ChatGPT (and other MCP Apps hosts) can render search results and a document preview instead of plain text. This is the first UI step toward a full ChatGPT sidebar app. Depends on #13958 (tools must return structuredContent first). Reference docs • Add UI to your MCP server (MCP Apps in ChatGPT, decoupled data/render tools, CSP): • MCP Apps specification: • OpenAI MCP Extensions spec (display modes, _meta["openai/ui"]): • TypeScript SDK README with registerAppResource / registerAppTool examples: • UI guidelines: • Example components (Pizzaz gallery): Current state • MCP server: server/routes/mcp/index.ts, tools in server/tools/*.ts. Capabilities are { tools: {}, resources: {} }. • One resource exists today: outline://icons (JSON). There are no ui:// resources and no tool uses _meta. • @modelcontextprotocol/sdk 1.29.0 is i…