Remove RAM and disk collection for services

Complete removal of service resource metrics:

Agent:
- Remove memory_mb and disk_gb fields from ServiceData struct
- Remove get_service_memory_usage() method
- Remove get_service_disk_usage() method
- Remove get_directory_size() method
- Remove unused warn import

Dashboard:
- Remove memory_mb and disk_gb from ServiceInfo struct
- Remove memory/disk display from format_parent_service_line
- Remove memory/disk parsing in legacy metric path
- Remove unused format_disk_size() function

Service resource metrics were slow, unreliable, and never worked
properly since structured data migration. Will be handled differently
in the future.

shared/src/agent_data.rs

@@ -136,8 +136,6 @@ pub struct PoolDriveData {
 #[derive(Debug, Clone, Serialize, Deserialize)]
 pub struct ServiceData {
     pub name: String,
-    pub memory_mb: f32,
-    pub disk_gb: f32,
     pub user_stopped: bool,
     pub service_status: Status,
     pub sub_services: Vec<SubServiceData>,