Default serve() to platform-ready configuration

[tomkis]

Is your feature request related to a problem? Please describe.
The Server.serve() method defaults to a minimal configuration (configure_telemetry=False, context_store=None → InMemoryContextStore, auth_backend=None), requiring developers to explicitly pass platform components every time. This makes the "happy path" unnecessarily verbose.

Describe the solution you'd like
Change defaults in Server.serve():

• configure_telemetry → True
• context_store → PlatformContextStore()
• auth_backend → PlatformAuthBackend()

Developers should only need to pass these parameters when overriding with custom implementations. Documentation and examples should be updated to reflect the new defaults.