Fix output scrolling - show only last 50 lines

Instead of trying to scroll the window, just display the most
recent lines that fit on screen. Full history is kept but only
the last 50 lines are rendered.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

agentserver/console/tui_console.py

@@ -87,9 +87,10 @@ STYLE = Style.from_dict({
 class OutputBuffer:
     """Manages scrolling output history."""
 
-    def __init__(self, max_lines: int = 1000):
+    def __init__(self, max_lines: int = 1000, visible_lines: int = 50):
         self.lines: List[tuple] = []  # (style_class, text)
         self.max_lines = max_lines
+        self.visible_lines = visible_lines  # Lines to show on screen
 
     def append(self, text: str, style: str = "output"):
         """Add a line to output."""
@@ -105,11 +106,13 @@ class OutputBuffer:
             self.lines = self.lines[-self.max_lines:]
 
     def get_formatted_text(self) -> FormattedText:
-        """Get formatted text for display."""
+        """Get formatted text for display - only show last N lines."""
+        # Only return the most recent lines that fit on screen
+        visible = self.lines[-self.visible_lines:] if len(self.lines) > self.visible_lines else self.lines
         result = []
-        for style, text in self.lines:
+        for style, text in visible:
             result.append((f"class:{style}", text))
-            result.append(("", "\n"))  # Newline as separate unstyled element
+            result.append(("", "\n"))
         return FormattedText(result)
 
     def clear(self):
@@ -185,18 +188,25 @@ class TUIConsole:
             """Handle Ctrl+L - clear output."""
             self.output.clear()
 
-        # Output area (scrolling)
+        # Output area (scrolling) - use scroll_offsets to keep bottom visible
         output_control = FormattedTextControl(
             text=lambda: self.output.get_formatted_text(),
             focusable=False,
         )
 
+        # Create window that always scrolls to bottom
+        from prompt_toolkit.layout.controls import UIContent
+
         output_window = Window(
             content=output_control,
             wrap_lines=True,
             right_margins=[ScrollbarMargin(display_arrows=True)],
+            always_hide_cursor=True,
         )
 
+        # Store reference so we can scroll
+        self.output_window = output_window
+
         # Separator line with status
         def get_separator():
             name = self.pump.config.name