feat(pipeline): add metrics collection and v2 run mode

- Add RenderStage adapter that handles rendering pipeline
- Add EffectPluginStage with proper EffectContext
- Add DisplayStage with init handling
- Add ItemsStage for pre-fetched items
- Add metrics collection to Pipeline (StageMetrics, FrameMetrics)
- Add get_metrics_summary() and reset_metrics() methods
- Add --pipeline and --pipeline-preset flags for v2 mode
- Add PipelineNode.metrics for self-documenting introspection
- Add introspect_new_pipeline() method with performance data
- Add mise tasks: run-v2, run-v2-demo, run-v2-poetry, run-v2-websocket, run-v2-firehose

engine/app.py

@@ -839,12 +839,17 @@ def run_preset_mode(preset_name: str):
 
 def main():
     from engine import config
-    from engine.pipeline import generate_pipeline_diagram
 
     if config.PIPELINE_DIAGRAM:
+        from engine.pipeline import generate_pipeline_diagram
+
         print(generate_pipeline_diagram())
         return
 
+    if config.PIPELINE_MODE:
+        run_pipeline_mode(config.PIPELINE_PRESET)
+        return
+
     if config.PIPELINE_DEMO:
         run_pipeline_demo()
         return
@@ -955,3 +960,128 @@ def main():
     print(f"  {G_DIM}> {config.HEADLINE_LIMIT} SIGNALS PROCESSED{RST}")
     print(f"  {W_GHOST}> end of stream{RST}")
     print()
+
+
+def run_pipeline_mode(preset_name: str = "demo"):
+    """Run using the new unified pipeline architecture."""
+    import effects_plugins
+    from engine.display import DisplayRegistry
+    from engine.effects import get_registry
+    from engine.fetch import fetch_all, fetch_poetry, load_cache
+    from engine.pipeline import (
+        Pipeline,
+        PipelineConfig,
+        get_preset,
+    )
+    from engine.pipeline.adapters import (
+        RenderStage,
+        create_items_stage,
+        create_stage_from_display,
+        create_stage_from_effect,
+    )
+
+    print("  \033[1;38;5;46mPIPELINE MODE\033[0m")
+    print("  \033[38;5;245mUsing unified pipeline architecture\033[0m")
+
+    effects_plugins.discover_plugins()
+
+    preset = get_preset(preset_name)
+    if not preset:
+        print(f"  \033[38;5;196mUnknown preset: {preset_name}\033[0m")
+        sys.exit(1)
+
+    print(f"  \033[38;5;245mPreset: {preset.name} - {preset.description}\033[0m")
+
+    params = preset.to_params()
+    params.viewport_width = 80
+    params.viewport_height = 24
+
+    pipeline = Pipeline(
+        config=PipelineConfig(
+            source=preset.source,
+            display=preset.display,
+            camera=preset.camera,
+            effects=preset.effects,
+        )
+    )
+
+    print("  \033[38;5;245mFetching content...\033[0m")
+    cached = load_cache()
+    if cached:
+        items = cached
+    elif preset.source == "poetry":
+        items, _, _ = fetch_poetry()
+    else:
+        items, _, _ = fetch_all()
+
+    if not items:
+        print("  \033[38;5;196mNo content available\033[0m")
+        sys.exit(1)
+
+    print(f"  \033[38;5;82mLoaded {len(items)} items\033[0m")
+
+    display = DisplayRegistry.create(preset.display)
+    if not display:
+        print(f"  \033[38;5;196mFailed to create display: {preset.display}\033[0m")
+        sys.exit(1)
+
+    display.init(80, 24)
+
+    effect_registry = get_registry()
+
+    pipeline.add_stage("source", create_items_stage(items, preset.source))
+    pipeline.add_stage(
+        "render",
+        RenderStage(
+            items,
+            width=80,
+            height=24,
+            camera_speed=params.camera_speed,
+            camera_mode=preset.camera,
+            firehose_enabled=params.firehose_enabled,
+        ),
+    )
+
+    for effect_name in preset.effects:
+        effect = effect_registry.get(effect_name)
+        if effect:
+            pipeline.add_stage(
+                f"effect_{effect_name}", create_stage_from_effect(effect, effect_name)
+            )
+
+    pipeline.add_stage("display", create_stage_from_display(display, preset.display))
+
+    pipeline.build()
+
+    if not pipeline.initialize():
+        print("  \033[38;5;196mFailed to initialize pipeline\033[0m")
+        sys.exit(1)
+
+    print("  \033[38;5;82mStarting pipeline...\033[0m")
+    print("  \033[38;5;245mPress Ctrl+C to exit\033[0m\n")
+
+    ctx = pipeline.context
+    ctx.params = params
+    ctx.set("display", display)
+    ctx.set("items", items)
+    ctx.set("pipeline", pipeline)
+
+    try:
+        frame = 0
+        while True:
+            params.frame_number = frame
+            ctx.params = params
+
+            result = pipeline.execute(items)
+            if result.success:
+                display.show(result.data)
+
+            time.sleep(1 / 60)
+            frame += 1
+
+    except KeyboardInterrupt:
+        pass
+    finally:
+        pipeline.cleanup()
+        display.cleanup()
+        print("\n  \033[38;5;245mPipeline stopped\033[0m")