perf: @setRuntimeSafety(false) + burst detection infrastructure

- fillRect: disable runtime safety for hot path (bounds pre-validated)
- drawGlyphBitmap: disable runtime safety for hot path
- Context: add burst detection (isSelectionBurstActive, markNavigationEvent)
- PanelFrameConfig: add burst_sensitive field
- PanelFrameResult: new struct for frame drawing results

Note: burst_sensitive mechanism available but not actively used
(causes visual flickering when suppressing panel content)

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

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

src/core/context.zig

@@ -102,6 +102,10 @@ pub const Context = struct {
     /// Set by application for non-dirty panels to save CPU while keeping input working.
     suppress_commands: bool = false,
 
+    /// Burst detection: timestamp of last navigation event (selection change)
+    /// Used by drawPanelFrame to auto-suppress burst_sensitive panels during rapid navigation
+    last_navigation_time: i64 = 0,
+
     /// Frame statistics
     stats: FrameStats,
 
@@ -665,10 +669,24 @@ pub const Context = struct {
         draw_shadow: bool = true,
         /// Draw bevel effect (default true)
         draw_bevel: bool = true,
+
+        // === Performance ===
+        /// Si true, el panel se auto-suprime durante ráfagas de navegación.
+        /// Paneles principales (listas, fichas) deben ser false.
+        /// Paneles secundarios (documentos) pueden ser true para mejor rendimiento.
+        burst_sensitive: bool = true,
+    };
+
+    /// Result of drawPanelFrame for LEGO-style control flow
+    pub const PanelFrameResult = struct {
+        /// True if color transition is still animating
+        animating: bool,
+        /// False if panel was suppressed - caller should return immediately
+        should_draw: bool,
     };
 
     /// Draw a complete panel frame with focus transition and 3D effects.
-    /// Returns true if the transition is still animating (need more frames).
+    /// Returns PanelFrameResult: check should_draw to know if panel content should be rendered.
     ///
     /// Supports two modes:
     /// - **Explicit**: Provide focus_bg, unfocus_bg, border_color directly
@@ -678,7 +696,11 @@ pub const Context = struct {
         rect: Layout.Rect,
         transition: *ColorTransition,
         config: PanelFrameConfig,
-    ) bool {
+    ) PanelFrameResult {
+        // Auto-supresión LEGO: detectar si el panel debe suprimir operaciones costosas
+        // El frame SIEMPRE se dibuja, pero should_draw indica si continuar con widgets/BD
+        const burst_suppressed = config.burst_sensitive and self.isSelectionBurstActive();
+
         // Determine colors: Z-Design derivation or explicit
         const focus_bg: Style.Color = blk: {
             if (config.base_color) |base| {
@@ -764,7 +786,8 @@ pub const Context = struct {
             }
         }
 
-        return animating;
+        // should_draw = false indica que el panel debe saltar operaciones costosas (BD, widgets)
+        return .{ .animating = animating, .should_draw = !burst_suppressed };
     }
 
     /// Resize the context
@@ -837,6 +860,23 @@ pub const Context = struct {
         }
     }
 
+    // =========================================================================
+    // BURST DETECTION: Para auto-supresión de paneles durante navegación rápida
+    // =========================================================================
+
+    /// Marca que ocurrió un evento de navegación (cambio de selección).
+    /// Llamar desde DataManager cuando notifica cambios de selección.
+    pub fn markNavigationEvent(self: *Self) void {
+        self.last_navigation_time = std.time.milliTimestamp();
+    }
+
+    /// Devuelve true si estamos en medio de una ráfaga de navegación.
+    /// Se considera ráfaga si pasaron menos de 100ms desde el último evento.
+    pub fn isSelectionBurstActive(self: *Self) bool {
+        const now = std.time.milliTimestamp();
+        return (now - self.last_navigation_time) < 100;
+    }
+
     /// Get rectangles of all dirty panels (for renderer).
     /// Returns slice allocated from frame arena (valid until next beginFrame).
     pub fn getDirtyPanelRects(self: *Self) []const Layout.Rect {

src/render/framebuffer.zig

@@ -114,6 +114,7 @@ pub const Framebuffer = struct {
     /// Draw a filled rectangle
     /// Optimized with SIMD-friendly @memset for solid colors (alpha=255)
     pub fn fillRect(self: *Self, x: i32, y: i32, w: u32, h: u32, color: Color) void {
+        @setRuntimeSafety(false); // Hot path: bounds already validated below
         const x_start = @max(0, x);
         const y_start = @max(0, y);
         const x_end = @min(@as(i32, @intCast(self.width)), x + @as(i32, @intCast(w)));

src/render/ttf.zig

@@ -320,6 +320,7 @@ pub const TtfFont = struct {
         color: Color,
         clip: Rect,
     ) void {
+        @setRuntimeSafety(false); // Hot path: bounds validated in visible region calculation
         _ = self;
 
         const width: u32 = glyph.metrics.width;