refactor: move deferred Markdown import to top-level with other Rich imports

The `from rich.markdown import Markdown` import was deferred inside a
nested closure in `_on_iteration_ended`, the only lazy module-level import
in the file. All other Rich components are imported at the top. Moving it
there makes the import surface consistent and predictable.

Co-authored-by: Ralphify <noreply@ralphify.co>

Author: 2 people

src/ralphify/_console_emitter.py

@@ -20,6 +20,7 @@
 from rich.console import Console, ConsoleOptions, Group, RenderResult
 from rich.live import Live
 from rich.markup import escape as escape_markup
+from rich.markdown import Markdown
 from rich.panel import Panel
 from rich.rule import Rule
 from rich.spinner import Spinner
@@ -1539,8 +1540,6 @@ def do_print() -> None:
                         f"  [dim]{_ICON_ARROW} {escape_markup(log_file)}[/]"
                     )
                 if result_text:
-                    from rich.markdown import Markdown
-
                     self._console.print(Markdown(result_text))
 
             self._print_or_defer_unlocked(do_print)