Module lifecycle 

Lifecycle state machine for the HTTP server.

The server follows a strict state progression:

Created → Starting → Running → Draining → Stopped
            ↓                    ↓
         Failed               Failed

State transitions

• Created → Starting: Server::start() is called
• Starting → Running: listener bound, accept loop polled, readiness signaled
• Starting → Failed: bind, configuration, or accept-loop startup failure
• Running → Draining: ServerHandle::shutdown() is called
• Draining → Stopped: all in-flight connections complete or deadline expires
• Draining → Failed: fatal runtime error during drain

Allowed operations per state

State	build	start	ready	shutdown	force_shutdown	wait
Created	yes	yes	-	stop	stop	err
Starting	-	err	yes	stop	stop	err
Running	-	err	ok	ok	ok	yes
Draining	-	err	err	idempot	ok	yes
Stopped	-	err	err	noop	noop	ok
Failed	-	err	err	noop	noop	err

Enums

LifecycleState

Server lifecycle states.