Expose an app operation as a typed pracht capability — one contract projected
into direct server calls, an HTTP endpoint, a route-scoped WebMCP page tool, and a remote MCP
tool — plus `defineApp({ agents })` trust config, typed clients,
`<Form capability>`, and `pracht eval` scenarios.
Use for "add a capability", "expose this to agents", "add an MCP tool", "add
WebMCP", "serve remote MCP", "make my app agent-callable".
