docs(documentation): Update server docs for v5 architecture

[RandomByte]

Reflect the new UI5 Server architecture in the user-facing docs.

Server.md: The watch-mode section claimed config files are not monitored and that config changes require a restart. The Supervisor and ProjectDefinitionWatcher now re-resolve the graph and re-create the serving stack behind a stable HTTP server on a definition change. Split the section: keep source monitoring under Watch Mode Behavior, add a Project Definition Changes section covering ui5.yaml / package.json / workspace config / --config / --dependency-definition watching and the git checkout case. Requests are held with an auto-reloading page while the graph re-resolves. The restart caveat now scopes to custom task and middleware implementation code.

index.md: Add Node.js API examples for starting a server via serve() and for embedding the middleware via serveMiddleware().

JIRA: CPOUI5FOUNDATION-1307

[KlattG]

Suggested change

	`serveMiddleware` assembles the UI5 middleware as a single connect/Express handler, for mounting into an HTTP server you own instead of starting one. It does not bind a port or attach the Live Reload WebSocket server.
	`serveMiddleware` assembles the UI5 middleware as a single connect/Express handler for mounting into an HTTP server you own instead of starting one. It does not bind a port or attach the LiveReload WebSocket server.