Clean up unused imports and fix build warnings

- Remove unused imports (Duration, HashMap, SharedError, DateTime, etc.)
- Fix unused variables by prefixing with underscore
- Remove redundant dashboard.toml config file
- Update theme imports to use only needed components
- Maintain all functionality while reducing warnings
- Add srv02 to predefined hosts configuration
- Remove unused broadcast_command methods

agent/src/collectors/mod.rs

@@ -1,5 +1,5 @@
 use async_trait::async_trait;
-use cm_dashboard_shared::{Metric, SharedError};
+use cm_dashboard_shared::Metric;
 use std::time::Duration;
 
 pub mod cached_collector;