Remove debug prints and unused code

- Remove all debug println statements
- Remove unused service_tracker module
- Remove unused struct fields and methods
- Remove empty placeholder files (cpu.rs, memory.rs, defaults.rs)
- Fix all compiler warnings
- Clean build with zero warnings

Version bump to 0.1.159

dashboard/src/ui/widgets/cpu.rs

@@ -1 +0,0 @@
-// This file is intentionally left minimal - CPU functionality is handled by the SystemWidget

dashboard/src/ui/widgets/memory.rs

@@ -1 +0,0 @@
-// This file is intentionally left minimal - Memory functionality is handled by the SystemWidget

dashboard/src/ui/widgets/mod.rs

@@ -1,7 +1,5 @@
 use cm_dashboard_shared::AgentData;
 
-pub mod cpu;
-pub mod memory;
 pub mod services;
 pub mod system;
 

dashboard/src/ui/widgets/system.rs

@@ -508,55 +508,6 @@ fn truncate_serial(serial: &str) -> String {
     }
 }
 
-/// Helper function to render a drive in a MergerFS pool
-fn render_mergerfs_drive<'a>(drive: &StorageDrive, tree_symbol: &'a str, lines: &mut Vec<Line<'a>>) {
-    let mut drive_details = Vec::new();
-    if let Some(temp) = drive.temperature {
-        drive_details.push(format!("T: {}°C", temp as i32));
-    }
-    if let Some(wear) = drive.wear_percent {
-        drive_details.push(format!("W: {}%", wear as i32));
-    }
-    
-    let drive_text = if !drive_details.is_empty() {
-        format!("{} {}", drive.name, drive_details.join(" "))
-    } else {
-        drive.name.clone()
-    };
-    
-    let mut drive_spans = vec![
-        Span::styled(tree_symbol, Typography::tree()),
-    ];
-    drive_spans.extend(StatusIcons::create_status_spans(drive.status.clone(), &drive_text));
-    lines.push(Line::from(drive_spans));
-}
-
-/// Helper function to render a drive in a storage pool
-fn render_pool_drive(drive: &StorageDrive, is_last: bool, lines: &mut Vec<Line<'_>>) {
-    let tree_symbol = if is_last { "    └─" } else { "    ├─" };
-    
-    let mut drive_details = Vec::new();
-    if let Some(temp) = drive.temperature {
-        drive_details.push(format!("T: {}°C", temp as i32));
-    }
-    if let Some(wear) = drive.wear_percent {
-        drive_details.push(format!("W: {}%", wear as i32));
-    }
-    
-    let drive_text = if !drive_details.is_empty() {
-        format!("● {} {}", drive.name, drive_details.join(" "))
-    } else {
-        format!("● {}", drive.name)
-    };
-    
-    let mut drive_spans = vec![
-        Span::styled(tree_symbol, Typography::tree()),
-        Span::raw(" "),
-    ];
-    drive_spans.extend(StatusIcons::create_status_spans(drive.status.clone(), &drive_text));
-    lines.push(Line::from(drive_spans));
-}
-
 impl SystemWidget {
     /// Render backup section for display
     fn render_backup(&self) -> Vec<Line<'_>> {
@@ -622,43 +573,6 @@ impl SystemWidget {
         lines
     }
 
-    /// Format time ago from timestamp
-    fn format_time_ago(&self, timestamp: u64) -> String {
-        let now = chrono::Utc::now().timestamp() as u64;
-        let seconds_ago = now.saturating_sub(timestamp);
-        
-        let hours = seconds_ago / 3600;
-        let minutes = (seconds_ago % 3600) / 60;
-        
-        if hours > 0 {
-            format!("{}h ago", hours)
-        } else if minutes > 0 {
-            format!("{}m ago", minutes)
-        } else {
-            "now".to_string()
-        }
-    }
-
-    /// Format time until from future timestamp  
-    fn format_time_until(&self, timestamp: u64) -> String {
-        let now = chrono::Utc::now().timestamp() as u64;
-        if timestamp <= now {
-            return "overdue".to_string();
-        }
-        
-        let seconds_until = timestamp - now;
-        let hours = seconds_until / 3600;
-        let minutes = (seconds_until % 3600) / 60;
-        
-        if hours > 0 {
-            format!("in {}h", hours)
-        } else if minutes > 0 {
-            format!("in {}m", minutes)
-        } else {
-            "soon".to_string()
-        }
-    }
-
     /// Render system widget  
     pub fn render(&mut self, frame: &mut Frame, area: Rect, hostname: &str, config: Option<&crate::config::DashboardConfig>) {
         let mut lines = Vec::new();