Adds VmAgentCommandService::getCommands(), scoping the shared
event_agent_commands table down to a single VM (agent_type=vm,
agent_uuid=$vm->uuid) via the new agentUuid filter on
AgentCommandsQueryFilter (nextdeveloper/events v1.2.10). Lets the
dashboard show a VM's command history and results without querying
/events/agent-commands directly.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>