chore: import upstream snapshot with attribution

python/samples/02-agents/harness/console/components/prompt_rule.py

@@ -0,0 +1,31 @@
+# Copyright (c) Microsoft. All rights reserved.
+
+"""Mode-colored horizontal rule."""
+
+from __future__ import annotations
+
+from textual.reactive import reactive
+from textual.widgets import Static
+
+
+class PromptRule(Static):
+    """A full-width horizontal rule colored by the current agent mode.
+
+    Renders a line of '─' characters across the terminal width,
+    colored to match the current mode (e.g., cyan for plan, green for execute).
+
+    Attributes:
+        rule_color: Rich color string for the rule (e.g., "cyan", "green").
+    """
+
+    rule_color: reactive[str] = reactive("cyan")
+
+    def render(self) -> str:
+        """Render the horizontal rule.
+
+        Returns:
+            Formatted string with Rich markup.
+        """
+        color = self.rule_color
+        width = self.size.width or 80
+        return f"[{color}]{'─' * width}[/{color}]"