docs(skills): fix himalaya CLI arg order and download flag

Closes #48835

The bundled himalaya skill and its website docs documented command
syntax that does not match Himalaya CLI v1.2.0.

Verified against pimalaya/himalaya v1.2.0 source:
- message move: MessageMoveCommand declares target_folder BEFORE
  envelopes (src/email/message/command/move.rs) -> usage is
  '<TARGET> <ID>...', so 'move 42 "Archive"' is wrong; correct is
  'move "Archive" 42'.
- message copy: same ordering in copy.rs.
- attachment download: AttachmentDownloadCommand exposes the flag as
  '-d, --downloads-dir <PATH>' (src/email/message/attachment/command/
  download.rs), not '--dir'.

Fixed in all three surfaces that carried the wrong examples:
- skills/email/himalaya/SKILL.md
- website/docs/.../email-himalaya.md
- website/i18n/zh-Hans/.../email-himalaya.md

skills/email/himalaya/SKILL.md

@@ -213,16 +213,16 @@ Note: `himalaya message write` without piped input opens `$EDITOR`. This works w
 
 ### Move/Copy Emails
 
-Move to folder:
+Move to folder (target folder comes first, then the message ID):
 
 ```bash
-himalaya message move 42 "Archive"
+himalaya message move "Archive" 42
 ```
 
-Copy to folder:
+Copy to folder (target folder comes first, then the message ID):
 
 ```bash
-himalaya message copy 42 "Important"
+himalaya message copy "Important" 42
 ```
 
 ### Delete an Email
@@ -270,7 +270,7 @@ himalaya attachment download 42
 Save to specific directory:
 
 ```bash
-himalaya attachment download 42 --dir ~/Downloads
+himalaya attachment download 42 --downloads-dir ~/Downloads
 ```
 
 ## Output Formats

website/docs/user-guide/skills/bundled/email/email-himalaya.md

@@ -226,13 +226,13 @@ Note: `himalaya message write` without piped input opens `$EDITOR`. This works w
 Move to folder:
 
 ```bash
-himalaya message move 42 "Archive"
+himalaya message move "Archive" 42
 ```
 
 Copy to folder:
 
 ```bash
-himalaya message copy 42 "Important"
+himalaya message copy "Important" 42
 ```
 
 ### Delete an Email
@@ -280,7 +280,7 @@ himalaya attachment download 42
 Save to specific directory:
 
 ```bash
-himalaya attachment download 42 --dir ~/Downloads
+himalaya attachment download 42 --downloads-dir ~/Downloads
 ```
 
 ## Output Formats

website/i18n/zh-Hans/docusaurus-plugin-content-docs/current/user-guide/skills/bundled/email/email-himalaya.md

@@ -217,13 +217,13 @@ himalaya message write -H "To:recipient@example.com" -H "Subject:Test" "Message
 移动到文件夹：
 
 ```bash
-himalaya message move 42 "Archive"
+himalaya message move "Archive" 42
 ```
 
 复制到文件夹：
 
 ```bash
-himalaya message copy 42 "Important"
+himalaya message copy "Important" 42
 ```
 
 ### 删除邮件
@@ -271,7 +271,7 @@ himalaya attachment download 42
 保存到指定目录：
 
 ```bash
-himalaya attachment download 42 --dir ~/Downloads
+himalaya attachment download 42 --downloads-dir ~/Downloads
 ```
 
 ## 输出格式