fix(tui): honor forced repaints

Invalidate the fullscreen and inline renderer frame timers so forced repaint requests cannot be dropped by the frame-rate limiter. Add coverage for both renderer paths at a low FPS.

Fixes #7

Author: kingwill101

pkgs/artisanal/lib/src/tui/renderer.dart

@@ -415,6 +415,9 @@ class FullScreenTuiRenderer implements TuiRenderer {
   void invalidate() {
     _lastView = null;
     _lastFrame = null;
+    // Invalidation is used by forced repaints. The next render must not be
+    // discarded just because the regular frame-rate interval has not elapsed.
+    _frameStopwatch.stop();
   }
 
   @override
@@ -613,6 +616,9 @@ class InlineTuiRenderer implements TuiRenderer {
   @override
   void invalidate() {
     _lastLineCount = 0;
+    // Invalidation is used by forced repaints. The next render must not be
+    // discarded just because the regular frame-rate interval has not elapsed.
+    _frameStopwatch.stop();
   }
 
   @override

pkgs/artisanal/test/tui/fullscreen_renderer_test.dart

@@ -49,6 +49,26 @@ void main() {
       expect(terminal.output, isNot(contains('alpha')));
     });
 
+    test('invalidate bypasses the frame-rate limiter', () {
+      final terminal = StringTerminal();
+      final renderer = FullScreenTuiRenderer(
+        terminal: terminal,
+        options: const TuiRendererOptions(
+          fps: 1,
+          altScreen: true,
+          hideCursor: false,
+        ),
+      );
+
+      renderer.render('same frame');
+      terminal.clear();
+
+      renderer.invalidate();
+      renderer.render('same frame');
+
+      expect(terminal.output, contains('same frame'));
+    });
+
     test('re-renders lines whose inherited ANSI state changed', () {
       final terminal = StringTerminal();
       final renderer = buildRenderer(terminal);
@@ -182,4 +202,24 @@ void main() {
       );
     });
   });
+
+  test('InlineTuiRenderer invalidate bypasses the frame-rate limiter', () {
+    final terminal = StringTerminal();
+    final renderer = InlineTuiRenderer(
+      terminal: terminal,
+      options: const TuiRendererOptions(
+        fps: 1,
+        altScreen: false,
+        hideCursor: false,
+      ),
+    );
+
+    renderer.render('same frame');
+    terminal.clear();
+
+    renderer.invalidate();
+    renderer.render('same frame');
+
+    expect(terminal.output, contains('same frame'));
+  });
 }