fix: Improve help screen rendering and docstring formatting

- Use Markdown widget for proper help text formatting
- Fix extra blank lines in run_tui docstring
- Resolves CodeRabbit actionable comments

cognee/cli/tui/app.py

@@ -5,7 +5,7 @@ Text-based User Interface for managing Cognee knowledge graphs
 from typing import ClassVar
 from textual.app import App, ComposeResult
 from textual.binding import Binding
-from textual.widgets import Header, Footer, Static, Button
+from textual.widgets import Header, Footer, Static, Button, Markdown
 from textual.containers import VerticalScroll
 from textual.screen import Screen
 from textual.events import Key
@@ -103,7 +103,7 @@ class HelpScreen(Screen):
     def compose(self) -> ComposeResult:
         yield Header()
         with VerticalScroll():
-            yield Static(self.help_text, markup=False)
+            yield Static(self.help_text)
         yield Button("Close (Esc)", id="close", variant="primary")
         yield Footer()