test(effects): add performance benchmark tests

- Add TestEffectPipelinePerformance test class
- test_pipeline_stays_within_frame_budget: verifies pipeline completes within 33ms (30fps)
- test_individual_effects_performance: verifies individual effects don't exceed 10ms

tests/test_effects.py

@@ -331,3 +331,97 @@ class TestPerformanceMonitor:
         monitor.reset()
         stats = monitor.get_stats()
         assert "error" in stats
+
+
+class TestEffectPipelinePerformance:
+    def test_pipeline_stays_within_frame_budget(self):
+        """Verify effect pipeline completes within frame budget (33ms for 30fps)."""
+        from engine.effects import (
+            EffectChain,
+            EffectConfig,
+            EffectContext,
+            EffectRegistry,
+        )
+
+        class DummyEffect:
+            name = "dummy"
+            config = EffectConfig(enabled=True, intensity=1.0)
+
+            def process(self, buf, ctx):
+                return [line * 2 for line in buf]
+
+        registry = EffectRegistry()
+        registry.register(DummyEffect())
+
+        from engine.effects.performance import PerformanceMonitor
+
+        monitor = PerformanceMonitor(max_frames=10)
+        chain = EffectChain(registry, monitor)
+        chain.set_order(["dummy"])
+
+        buf = ["x" * 80] * 20
+
+        for i in range(10):
+            ctx = EffectContext(
+                terminal_width=80,
+                terminal_height=24,
+                scroll_cam=0,
+                ticker_height=20,
+                mic_excess=0.0,
+                grad_offset=0.0,
+                frame_number=i,
+                has_message=False,
+            )
+            chain.process(buf, ctx)
+
+        stats = monitor.get_stats()
+        assert "error" not in stats
+        assert stats["pipeline"]["max_ms"] < 33.0
+
+    def test_individual_effects_performance(self):
+        """Verify individual effects don't exceed 10ms per frame."""
+        from engine.effects import (
+            EffectChain,
+            EffectConfig,
+            EffectContext,
+            EffectRegistry,
+        )
+
+        class SlowEffect:
+            name = "slow"
+            config = EffectConfig(enabled=True, intensity=1.0)
+
+            def process(self, buf, ctx):
+                result = []
+                for line in buf:
+                    result.append(line)
+                    result.append(line + line)
+                return result
+
+        registry = EffectRegistry()
+        registry.register(SlowEffect())
+
+        from engine.effects.performance import PerformanceMonitor
+
+        monitor = PerformanceMonitor(max_frames=5)
+        chain = EffectChain(registry, monitor)
+        chain.set_order(["slow"])
+
+        buf = ["x" * 80] * 10
+
+        for i in range(5):
+            ctx = EffectContext(
+                terminal_width=80,
+                terminal_height=24,
+                scroll_cam=0,
+                ticker_height=20,
+                mic_excess=0.0,
+                grad_offset=0.0,
+                frame_number=i,
+                has_message=False,
+            )
+            chain.process(buf, ctx)
+
+        stats = monitor.get_stats()
+        assert "error" not in stats
+        assert stats["effects"]["slow"]["max_ms"] < 10.0