chore(cli): standardize help and usage errors

Author: pallyoung

docs/development/cli.en.md

@@ -96,6 +96,12 @@ Additional flags on specific commands:
 - `config password set --stdin`: reads the passphrase from stdin
 - `auth ip unblock --all`: removes all currently blocked IPs at once
 
+## Exit Codes
+
+- `0`: success
+- `1`: runtime or operation failure
+- `2`: command usage, argument, or input validation failure
+
 ## Runtime Commands
 
 ### `start`

docs/development/cli.md

@@ -96,6 +96,12 @@ coder-studio --version
 - `config password set --stdin`：从标准输入读取口令
 - `auth ip unblock --all`：一次解除全部当前封禁 IP
 
+## 退出码
+
+- `0`：执行成功
+- `1`：运行时或操作失败
+- `2`：命令用法、参数或输入值错误
+
 ## 运行时命令
 
 ### `start`