Add mouse support and improve terminal resize handling

- Add mouse click support for hostname selection in title bar
- Fix right-aligned hostname position calculation
- Add mouse scroll support for both panels
- Add mouse click to select service rows
- Add right-click popup menu for service actions (Start/Stop/Logs)
- Add hover highlighting for popup menu items
- Improve terminal resize crash protection with 90x15 minimum size
- Add "Host:" prefix and separators to status bar
- Move NixOS metrics from system panel to status bar
- Change "... X more below" indicator to use border color
- Remove service name from popup menu title

dashboard/src/ui/widgets/system.rs

@@ -1,12 +1,13 @@
 use cm_dashboard_shared::Status;
 use ratatui::{
     layout::Rect,
+    style::Style,
     text::{Line, Span, Text},
     widgets::Paragraph,
     Frame,
 };
 
-use crate::ui::theme::{StatusIcons, Typography};
+use crate::ui::theme::{StatusIcons, Theme, Typography};
 
 /// System widget displaying NixOS info, Network, CPU, RAM, and Storage in unified layout
 #[derive(Clone)]
@@ -49,6 +50,11 @@ pub struct SystemWidget {
     
     // Overall status
     has_data: bool,
+
+    // Scroll offset for viewport
+    pub scroll_offset: usize,
+    /// Last rendered viewport height (for accurate scroll bounds)
+    last_viewport_height: usize,
 }
 
 #[derive(Clone)]
@@ -110,6 +116,8 @@ impl SystemWidget {
             backup_repository_status: Status::Unknown,
             backup_disks: Vec::new(),
             has_data: false,
+            scroll_offset: 0,
+            last_viewport_height: 0,
         }
     }
 
@@ -153,6 +161,16 @@ impl SystemWidget {
     pub fn _get_agent_hash(&self) -> Option<&String> {
         self.agent_hash.as_ref()
     }
+
+    /// Get the build version
+    pub fn get_build_version(&self) -> Option<String> {
+        self.nixos_build.clone()
+    }
+
+    /// Get the agent version
+    pub fn get_agent_version(&self) -> Option<String> {
+        self.agent_hash.clone()
+    }
 }
 
 use super::Widget;
@@ -206,6 +224,16 @@ impl Widget for SystemWidget {
         self.backup_repositories = backup.repositories.clone();
         self.backup_repository_status = backup.repository_status;
         self.backup_disks = backup.disks.clone();
+
+        // Clamp scroll offset to valid range after update
+        // This prevents scroll issues when switching between hosts
+        let total_lines = self.get_total_lines();
+        if total_lines == 0 {
+            self.scroll_offset = 0;
+        } else if self.scroll_offset >= total_lines {
+            // Clamp to max valid value, not reset to 0
+            self.scroll_offset = total_lines.saturating_sub(1);
+        }
     }
 }
 
@@ -781,23 +809,90 @@ impl SystemWidget {
     }
 
     /// 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();
+    /// Scroll down by one line
+    pub fn scroll_down(&mut self, _visible_height: usize, _total_lines: usize) {
+        let total_lines = self.get_total_lines();
 
-        // NixOS section
-        lines.push(Line::from(vec![
-            Span::styled(format!("NixOS {}:", hostname), Typography::widget_title())
-        ]));
-        
-        let build_text = self.nixos_build.as_deref().unwrap_or("unknown");
-        lines.push(Line::from(vec![
-            Span::styled(format!("Build: {}", build_text), Typography::secondary())
-        ]));
-        
-        let agent_version_text = self.agent_hash.as_deref().unwrap_or("unknown");
-        lines.push(Line::from(vec![
-            Span::styled(format!("Agent: {}", agent_version_text), Typography::secondary())
-        ]));
+        // Use last_viewport_height if available (more accurate), otherwise can't scroll
+        let viewport_height = if self.last_viewport_height > 0 {
+            self.last_viewport_height
+        } else {
+            return; // Can't scroll without knowing viewport size
+        };
+
+        // Max scroll should allow us to see all remaining content
+        // When scroll_offset + viewport_height >= total_lines, we can see everything
+        let max_scroll = if total_lines > viewport_height {
+            total_lines - viewport_height
+        } else {
+            0
+        };
+
+        if self.scroll_offset < max_scroll {
+            self.scroll_offset += 1;
+        }
+    }
+
+    /// Scroll up by one line
+    pub fn scroll_up(&mut self) {
+        if self.scroll_offset > 0 {
+            self.scroll_offset -= 1;
+        }
+    }
+
+    /// Get total line count (needs to be calculated before rendering)
+    pub fn get_total_lines(&self) -> usize {
+        let mut count = 0;
+
+        // CPU section (2+ lines for load/cstate, +1 if has model/cores)
+        count += 2;
+        if self.cpu_model_name.is_some() || self.cpu_core_count.is_some() {
+            count += 1;
+        }
+
+        // RAM section (1 + tmpfs mounts)
+        count += 2;
+        count += self.tmpfs_mounts.len();
+
+        // Network section
+        if !self.network_interfaces.is_empty() {
+            count += 1; // Header
+            // Count network lines (would need to mirror render_network logic)
+            for iface in &self.network_interfaces {
+                count += 1; // Interface name
+                count += iface.ipv4_addresses.len();
+                count += iface.ipv6_addresses.len();
+            }
+        }
+
+        // Storage section
+        count += 1; // Header
+        for pool in &self.storage_pools {
+            count += 1; // Pool header
+            count += pool.drives.len();
+            count += pool.data_drives.len();
+            count += pool.parity_drives.len();
+            count += pool.filesystems.len();
+        }
+
+        // Backup section
+        if !self.backup_repositories.is_empty() || !self.backup_disks.is_empty() {
+            count += 1; // Header
+            if !self.backup_repositories.is_empty() {
+                count += 1; // Repo header
+                count += self.backup_repositories.len();
+            }
+            count += self.backup_disks.len() * 3; // Each disk has 3 lines
+        }
+
+        count
+    }
+
+    pub fn render(&mut self, frame: &mut Frame, area: Rect, _hostname: &str, _config: Option<&crate::config::DashboardConfig>) {
+        // Store viewport height for accurate scroll calculations
+        self.last_viewport_height = area.height as usize;
+
+        let mut lines = Vec::new();
 
         // CPU section
         lines.push(Line::from(vec![
@@ -905,29 +1000,51 @@ impl SystemWidget {
         // Apply scroll offset
         let total_lines = lines.len();
         let available_height = area.height as usize;
-        
-        // Show only what fits, with "X more below" if needed
-        if total_lines > available_height {
-            let lines_for_content = available_height.saturating_sub(1); // Reserve one line for "more below"
-            let mut visible_lines: Vec<Line> = lines
-                .into_iter()
-                .take(lines_for_content)
-                .collect();
-            
-            let hidden_below = total_lines.saturating_sub(lines_for_content);
-            if hidden_below > 0 {
-                let more_line = Line::from(vec![
-                    Span::styled(format!("... {} more below", hidden_below), Typography::muted())
-                ]);
-                visible_lines.push(more_line);
-            }
-            
-            let paragraph = Paragraph::new(Text::from(visible_lines));
-            frame.render_widget(paragraph, area);
+
+        // Clamp scroll_offset to valid range based on current viewport and content
+        // This handles dynamic viewport size changes
+        let max_valid_scroll = total_lines.saturating_sub(available_height);
+        let clamped_scroll = self.scroll_offset.min(max_valid_scroll);
+
+        // Calculate how many lines remain after scroll offset
+        let remaining_lines = total_lines.saturating_sub(clamped_scroll);
+
+        // Check if all remaining content fits in viewport
+        let will_show_more_below = remaining_lines > available_height;
+
+        // Reserve one line for "X more below" only if we can't fit everything
+        let lines_for_content = if will_show_more_below {
+            available_height.saturating_sub(1)
         } else {
-            // All content fits and no scroll offset, render normally
-            let paragraph = Paragraph::new(Text::from(lines));
-            frame.render_widget(paragraph, area);
+            available_height.min(remaining_lines)
+        };
+
+        // Apply clamped scroll offset and take only what fits
+        let mut visible_lines: Vec<Line> = lines
+            .into_iter()
+            .skip(clamped_scroll)
+            .take(lines_for_content)
+            .collect();
+
+        // Note: we don't update self.scroll_offset here due to borrow checker constraints
+        // It will be clamped on next render if still out of bounds
+
+        // Only calculate hidden_below if we actually reserved space for the message
+        let hidden_below = if will_show_more_below {
+            remaining_lines.saturating_sub(lines_for_content)
+        } else {
+            0
+        };
+
+        // Add "more below" message if needed
+        if hidden_below > 0 {
+            let more_line = Line::from(vec![
+                Span::styled(format!("... {} more below", hidden_below), Style::default().fg(Theme::border()))
+            ]);
+            visible_lines.push(more_line);
         }
+
+        let paragraph = Paragraph::new(Text::from(visible_lines));
+        frame.render_widget(paragraph, area);
     }
 }