fix(cli): use display-width for response box header label to support CJK

Replace `len(label)` with `HermesCLI._status_bar_display_width(label)`
in two places where the response box top border is rendered.

`len()` counts characters, not terminal columns. CJK characters like
`测` and `试` each occupy 2 columns, causing the top border
`╭─ 测试 ───╮` to render 2 columns wider than the bottom border
`╰─────────╯`.

The `_status_bar_display_width` helper already exists (line 2881) and
uses `prompt_toolkit.utils.get_cwidth` for proper CJK width calculation.

cli.py

@@ -3669,7 +3669,7 @@ class HermesCLI:
             if self.show_timestamps:
                 label = f"{label} {datetime.now().strftime('%H:%M')}"
             w = shutil.get_terminal_size().columns
-            fill = w - 2 - len(label)
+            fill = w - 2 - HermesCLI._status_bar_display_width(label)
             _cprint(f"\n{_ACCENT}╭─{label}{'─' * max(fill - 1, 0)}╮{_RST}")
 
         self._stream_buf += text
@@ -10393,7 +10393,7 @@ class HermesCLI:
                         label = " ⚕ Hermes "
                         if self.show_timestamps:
                             label = f"{label}{datetime.now().strftime('%H:%M')} "
-                        fill = w - 2 - len(label)
+                        fill = w - 2 - HermesCLI._status_bar_display_width(label)
                         _cprint(f"\n{_ACCENT}╭─{label}{'─' * max(fill - 1, 0)}╮{_RST}")
                     _cprint(f"{_STREAM_PAD}{sentence.rstrip()}")