refactor: extract _format_info helper for info string

Single source of truth for the hint and character count template,
used by both the initial textbox info and the change handler.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

app.py

@@ -86,8 +86,12 @@ def translate(
     return result
 
 
+def _format_info(char_count: int) -> str:
+    return f"Press Ctrl+Enter to apply · {char_count} / 2,000"
+
+
 def _update_char_count(text: str) -> dict:
-    return gr.update(info=f"Press Ctrl+Enter to apply · {len(text)} / 2,000")
+    return gr.update(info=_format_info(len(text)))
 
 
 def _translate_with_loading(
@@ -115,7 +119,7 @@ def _build_demo() -> gr.Blocks:
                     lines=6,
                     show_label=False,
                     buttons=["clear"],
-                    info="Press Ctrl+Enter to apply · 0 / 2,000",
+                    info=_format_info(0),
                 )
             with gr.Column():
                 target_language = gr.Dropdown(