feat(server): integrate SpawnMixin into AMCHandler

amc_server/handler.py

@@ -6,6 +6,7 @@ from amc_server.mixins.discovery import SessionDiscoveryMixin
 from amc_server.mixins.http import HttpMixin
 from amc_server.mixins.parsing import SessionParsingMixin
 from amc_server.mixins.skills import SkillsMixin
+from amc_server.mixins.spawn import SpawnMixin
 from amc_server.mixins.state import StateMixin
 
 
@@ -17,6 +18,7 @@ class AMCHandler(
     SessionDiscoveryMixin,
     SessionParsingMixin,
     SkillsMixin,
+    SpawnMixin,
     BaseHTTPRequestHandler,
 ):
     """HTTP handler composed from focused mixins."""