fix(performance): use simple height estimation instead of PIL rendering

- Replace estimate_block_height (PIL-based) with estimate_simple_height (word wrap)
- Update viewport filter tests to match new height-based filtering (~4 items vs 24)
- Fix CI task duplication in mise.toml (remove redundant depends)

Closes #38
Closes #36

engine/pipeline/adapters/display.py

@@ -0,0 +1,50 @@
+"""Adapter wrapping Display as a Stage."""
+
+from typing import Any
+
+from engine.pipeline.core import PipelineContext, Stage
+
+
+class DisplayStage(Stage):
+    """Adapter wrapping Display as a Stage."""
+
+    def __init__(self, display, name: str = "terminal"):
+        self._display = display
+        self.name = name
+        self.category = "display"
+        self.optional = False
+
+    @property
+    def capabilities(self) -> set[str]:
+        return {"display.output"}
+
+    @property
+    def dependencies(self) -> set[str]:
+        return {"render.output"}  # Display needs rendered content
+
+    @property
+    def inlet_types(self) -> set:
+        from engine.pipeline.core import DataType
+
+        return {DataType.TEXT_BUFFER}  # Display consumes rendered text
+
+    @property
+    def outlet_types(self) -> set:
+        from engine.pipeline.core import DataType
+
+        return {DataType.NONE}  # Display is a terminal stage (no output)
+
+    def init(self, ctx: PipelineContext) -> bool:
+        w = ctx.params.viewport_width if ctx.params else 80
+        h = ctx.params.viewport_height if ctx.params else 24
+        result = self._display.init(w, h, reuse=False)
+        return result is not False
+
+    def process(self, data: Any, ctx: PipelineContext) -> Any:
+        """Output data to display."""
+        if data is not None:
+            self._display.show(data)
+        return data
+
+    def cleanup(self) -> None:
+        self._display.cleanup()