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

dashboard/src/ui/widgets/backup.rs

@@ -7,7 +7,7 @@ use ratatui::{
 use tracing::debug;
 
 use super::Widget;
-use crate::ui::theme::{Theme, Typography, Components, StatusIcons};
+use crate::ui::theme::{Typography, StatusIcons};
 
 /// Backup widget displaying backup status, services, and repository information
 #[derive(Clone)]

dashboard/src/ui/widgets/cpu.rs

@@ -7,7 +7,7 @@ use ratatui::{
 use tracing::debug;
 
 use super::Widget;
-use crate::ui::theme::{Theme, Typography, Components, StatusIcons};
+use crate::ui::theme::{Typography, StatusIcons};
 
 /// CPU widget displaying load, temperature, and frequency
 #[derive(Clone)]

dashboard/src/ui/widgets/memory.rs

@@ -7,7 +7,7 @@ use ratatui::{
 use tracing::debug;
 
 use super::Widget;
-use crate::ui::theme::{Theme, Typography, Components, StatusIcons};
+use crate::ui::theme::{Typography, StatusIcons};
 
 /// Memory widget displaying usage, totals, and swap information
 #[derive(Clone)]