fix(cli): add 'detail' subcommand to /context command

The /context command was missing the subcommand autocomplete feature
that other commands like /stats have. Now users can type '/context '
and see 'detail' as a suggestion in the dropdown.

- Added 'detail' subCommand to contextCommand with its own description
- Subcommand delegates to main action with 'detail' arg
- Added missing translation key for full description in zh.js
- Updated commands.md documentation

Co-authored-by: Qwen-Coder <qwen-coder@alibabacloud.com>

docs/users/features/commands.md

@@ -34,6 +34,7 @@ Commands for adjusting interface appearance and work environment.
 | ------------ | ---------------------------------------- | ----------------------------- |
 | `/clear`     | Clear terminal screen content            | `/clear` (shortcut: `Ctrl+L`) |
 | `/context`   | Show context window usage breakdown      | `/context`                    |
+| → `detail`   | Show per-item context usage breakdown    | `/context detail`             |
 | `/theme`     | Change Qwen Code visual theme            | `/theme`                      |
 | `/vim`       | Turn input area Vim editing mode on/off  | `/vim`                        |
 | `/directory` | Manage multi-directory support workspace | `/dir add ./src,./tests`      |