feat: Hybrid cursor blink - blinks while active, solid when idle

Implement user-friendly cursor behavior:
- Cursor blinks (500ms on/off) while there's user activity
- After 5 seconds of inactivity, cursor becomes solid (always visible)
- Any input (keyboard, mouse move, click, scroll) resets the timer

Changes:
- context.zig: Add last_input_time_ms tracking
- input.zig: Add hasActivity() and hasActivityWithMouse() methods
- input.zig: Track mouse_x_prev/mouse_y_prev for movement detection
- text_input.zig: Implement hybrid blink logic

This saves battery on laptops while maintaining natural cursor feedback.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

src/core/context.zig

@@ -95,6 +95,10 @@ pub const Context = struct {
     /// Time delta since last frame in milliseconds
     frame_delta_ms: u32 = 0,
 
+    /// Last time there was user input (keyboard or mouse activity)
+    /// Used for idle detection (e.g., cursor stops blinking after inactivity)
+    last_input_time_ms: u64 = 0,
+
     const Self = @This();
 
     /// Frame statistics for performance monitoring
@@ -186,6 +190,11 @@ pub const Context = struct {
         // Focus system frame end (processes Tab navigation)
         self.focus.endFrame();
 
+        // Update last input time if there was activity this frame
+        if (self.input.hasActivityWithMouse() and self.current_time_ms > 0) {
+            self.last_input_time_ms = self.current_time_ms;
+        }
+
         self.input.endFrame();
 
         // Update final stats

src/core/input.zig

@@ -172,6 +172,10 @@ pub const InputState = struct {
     mouse_x: i32 = 0,
     mouse_y: i32 = 0,
 
+    // Mouse position (previous frame, for detecting movement)
+    mouse_x_prev: i32 = 0,
+    mouse_y_prev: i32 = 0,
+
     // Mouse buttons (current frame)
     mouse_down: [5]bool = .{ false, false, false, false, false },
 
@@ -210,6 +214,8 @@ pub const InputState = struct {
     pub fn endFrame(self: *Self) void {
         self.mouse_down_prev = self.mouse_down;
         self.keys_down_prev = self.keys_down;
+        self.mouse_x_prev = self.mouse_x;
+        self.mouse_y_prev = self.mouse_y;
         self.scroll_x = 0;
         self.scroll_y = 0;
         self.text_input_len = 0;
@@ -367,6 +373,36 @@ pub const InputState = struct {
         }
         return null;
     }
+
+    /// Check if there was any user activity this frame (keyboard or mouse)
+    /// Used for idle detection (cursor blinking, screensaver, etc.)
+    pub fn hasActivity(self: Self) bool {
+        // Key events this frame
+        if (self.key_event_count > 0) return true;
+
+        // Text input this frame
+        if (self.text_input_len > 0) return true;
+
+        // Mouse button changes
+        for (self.mouse_down, 0..) |down, i| {
+            if (down != self.mouse_down_prev[i]) return true;
+        }
+
+        // Scroll activity
+        if (self.scroll_x != 0 or self.scroll_y != 0) return true;
+
+        return false;
+    }
+
+    /// Check if there was any activity including mouse movement
+    pub fn hasActivityWithMouse(self: Self) bool {
+        if (self.hasActivity()) return true;
+
+        // Mouse movement
+        if (self.mouse_x != self.mouse_x_prev or self.mouse_y != self.mouse_y_prev) return true;
+
+        return false;
+    }
 };
 
 // =============================================================================

src/widgets/text_input.zig

@@ -351,20 +351,33 @@ pub fn textInputRect(
         ctx.pushCommand(Command.text(inner.x, text_y, display_text, display_color));
     }
 
-    // Draw cursor if focused (blinking every 500ms)
+    // Draw cursor if focused
+    // Hybrid behavior: blinks while active, solid after idle timeout
     if (has_focus and !config.readonly) {
-        // Cursor blinks: visible for 500ms, hidden for 500ms
+        const char_width: u32 = 8;
-        const blink_period_ms: u64 = 500;
+        const cursor_x = inner.x + @as(i32, @intCast(state.cursor * char_width));
-        const cursor_visible = if (ctx.current_time_ms > 0)
+        const cursor_color = theme.foreground;
-            (ctx.current_time_ms / blink_period_ms) % 2 == 0
+
-        else
+        // Determine if cursor should be visible
-            true; // Always visible if no timing available
+        const cursor_visible = blk: {
+            // If no timing available, always show cursor
+            if (ctx.current_time_ms == 0) break :blk true;
+
+            // Check idle time (time since last user input)
+            const idle_timeout_ms: u64 = 5000; // 5 seconds
+            const idle_time = ctx.current_time_ms -| ctx.last_input_time_ms;
+
+            if (idle_time >= idle_timeout_ms) {
+                // Idle: cursor always visible (solid, no blink)
+                break :blk true;
+            } else {
+                // Active: cursor blinks (visible for 500ms, hidden for 500ms)
+                const blink_period_ms: u64 = 500;
+                break :blk (ctx.current_time_ms / blink_period_ms) % 2 == 0;
+            }
+        };
 
         if (cursor_visible) {
-            const char_width: u32 = 8;
-            const cursor_x = inner.x + @as(i32, @intCast(state.cursor * char_width));
-            const cursor_color = theme.foreground;
-
             ctx.pushCommand(Command.rect(
                 cursor_x,
                 inner.y,