fix: change case sensitivity toggle to Alt+C

Ctrl+I sends the same keycode as Tab in terminals, making it unusable.
Changed to Alt+C and updated help overlay to show filter keybindings.

Also fixed history tests to be independent of persisted history.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: raaymax

src/app.rs

@@ -887,37 +887,40 @@ mod tests {
     fn test_add_to_history() {
         let temp_file = create_temp_log_file(&["line"]);
         let mut app = App::new(vec![temp_file.path().to_path_buf()], false).unwrap();
+        let initial_len = app.filter_history.len();
 
         // Add patterns to history
         app.add_to_history("ERROR".to_string(), FilterMode::plain());
         app.add_to_history("WARN".to_string(), FilterMode::plain());
         app.add_to_history("INFO".to_string(), FilterMode::plain());
 
-        assert_eq!(app.filter_history.len(), 3);
+        assert_eq!(app.filter_history.len(), initial_len + 3);
     }
 
     #[test]
     fn test_add_to_history_skips_duplicates() {
         let temp_file = create_temp_log_file(&["line"]);
         let mut app = App::new(vec![temp_file.path().to_path_buf()], false).unwrap();
+        let initial_len = app.filter_history.len();
 
-        app.add_to_history("ERROR".to_string(), FilterMode::plain());
-        app.add_to_history("ERROR".to_string(), FilterMode::plain()); // Duplicate - should not add
+        app.add_to_history("ERROR_DUP_TEST".to_string(), FilterMode::plain());
+        app.add_to_history("ERROR_DUP_TEST".to_string(), FilterMode::plain()); // Duplicate - should not add
 
-        assert_eq!(app.filter_history.len(), 1);
+        assert_eq!(app.filter_history.len(), initial_len + 1);
     }
 
     #[test]
     fn test_add_to_history_same_pattern_different_mode() {
         let temp_file = create_temp_log_file(&["line"]);
         let mut app = App::new(vec![temp_file.path().to_path_buf()], false).unwrap();
+        let initial_len = app.filter_history.len();
 
-        app.add_to_history("error".to_string(), FilterMode::plain());
-        app.add_to_history("error".to_string(), FilterMode::regex()); // Different mode - should add
+        app.add_to_history("error_mode_test".to_string(), FilterMode::plain());
+        app.add_to_history("error_mode_test".to_string(), FilterMode::regex()); // Different mode - should add
 
-        assert_eq!(app.filter_history.len(), 2);
-        assert!(!app.filter_history[0].mode.is_regex());
-        assert!(app.filter_history[1].mode.is_regex());
+        assert_eq!(app.filter_history.len(), initial_len + 2);
+        assert!(!app.filter_history[initial_len].mode.is_regex());
+        assert!(app.filter_history[initial_len + 1].mode.is_regex());
     }
 
     #[test]

src/event.rs

@@ -20,7 +20,7 @@ pub enum AppEvent {
     FilterInputCancel,
     ClearFilter,
     ToggleFilterMode,      // Tab in filter input - switch Plain/Regex
-    ToggleCaseSensitivity, // Ctrl+I in filter input
+    ToggleCaseSensitivity, // Alt+C in filter input
     CursorLeft,            // Move cursor left in input
     CursorRight,           // Move cursor right in input
     CursorHome,            // Move cursor to start of input

src/handlers/input.rs

@@ -33,8 +33,8 @@ fn handle_help_mode(key: KeyEvent) -> Vec<AppEvent> {
 /// Handle keyboard input in filter input mode
 fn handle_filter_input_mode(key: KeyEvent) -> Vec<AppEvent> {
     match key.code {
-        // Ctrl+I toggles case sensitivity
-        KeyCode::Char('i') if key.modifiers.contains(KeyModifiers::CONTROL) => {
+        // Alt+C toggles case sensitivity (Ctrl+I doesn't work - same as Tab in terminals)
+        KeyCode::Char('c') if key.modifiers.contains(KeyModifiers::ALT) => {
             vec![AppEvent::ToggleCaseSensitivity]
         }
         // Ctrl+A goes to start of line

src/ui/mod.rs

@@ -597,6 +597,8 @@ fn render_help_overlay(f: &mut Frame, area: Rect) {
                 .add_modifier(Modifier::BOLD),
         )]),
         Line::from("  /             Start live filter"),
+        Line::from("  Tab           Toggle Plain/Regex mode"),
+        Line::from("  Alt+C         Toggle case sensitivity"),
         Line::from("  Enter         Close filter input (keep filter)"),
         Line::from("  Esc           Clear filter / Cancel input"),
         Line::from("  Up/Down       Navigate filter history"),