feat: 新增修改密码和注销账号功能

新增修改密码和注销账号的API接口，实现用户通过验证旧密码修改密码，以及通过短信验证流程注销账号的功能，同时补充相关常量和文档说明。

docs/IM-前后端对接文档.md

@@ -943,7 +943,7 @@ X-MeetingIM-APIKey: <预置的普通 API Key>
 
 **状态：新增。**
 
-- 敏感操作先调用 `POST /v1/im/security/challenges`；开启青少年模式设置独立密码时 Body 为 `{"scene":"set_independent_password","channel":"sms"}`，关闭青少年模式时 Body 为 `{"scene":"close_youth_mode","channel":"sms"}`；群主转让使用 `{"scene":"group_owner_transfer","channel":"sms"}`；解散群聊使用 `{"scene":"group_dissolve","channel":"sms"}`。手机号由登录身份读取，客户端不提交目标手机号。
+- 敏感操作先调用 `POST /v1/im/security/challenges`；开启青少年模式设置独立密码时 Body 为 `{"scene":"set_independent_password","channel":"sms"}`，关闭青少年模式时 Body 为 `{"scene":"close_youth_mode","channel":"sms"}`；群主转让使用 `{"scene":"group_owner_transfer","channel":"sms"}`；解散群聊使用 `{"scene":"group_dissolve","channel":"sms"}`；注销账号使用 `{"scene":"delete_account","channel":"sms"}`。手机号由登录身份读取，客户端不提交目标手机号。
 - 发码/校验：服务端返回 `challenge_id` 和脱敏手机号；提交 `POST /v1/im/security/challenges/{id}/verify`，Body `{"code":"..."}`。
 - 重复发码：同一用户、同一手机号、同一敏感场景存在未过期 challenge 且仍在 `resend_after_seconds` 冷却期内时，服务端返回 HTTP `429 VERIFICATION_RATE_LIMITED`，`details` 带 `challenge_id` 和 `retry_after_seconds`。客户端应复用该 `challenge_id` 继续倒计时，不要当成接口不可达或重新登录。
 - 小时限流：超过一小时创建次数上限时同样返回 HTTP `429 VERIFICATION_RATE_LIMITED`，`details.retry_after_seconds` 可能大于 60 秒且不一定带 `challenge_id`。客户端只展示倒计时，倒计时结束后允许用户重新获取验证码。
@@ -969,7 +969,7 @@ X-MeetingIM-APIKey: <预置的普通 API Key>
 
 - 页面只调用 `GET /v1/im/security/realname`。`verified` 时返回如 `masked_name:"张*"`、`masked_id_number:"110***********1234"`、`verified_at`。
 - 前端只读展示，不缓存原始证件信息，不提供直接修改接口。
-- 更正信息使用独立申诉 `POST /v1/im/security/realname/appeals`，需二次身份验证；不复用本页保存按钮。
+- 更正信息使用独立申诉 `POST /v1/im/security/realname/appeals`，Body `{"reason":"...","attachments":[]}`（`reason` 必填、≤500 字；`attachments` 最多 9 个 file_id），Bearer 即可，当前无需二次身份验证；不复用本页保存按钮。
 
 ### 1.10 实名认证（安卓）.png
 
@@ -3179,9 +3179,29 @@ GET /v1/im/topics/{topic}/message-mutations?since_version={localMutationVersion}
 | `POST /v1/im/security/challenges/{id}/verify` 关闭青少年模式 | `{"code":"123456"}` | `{"action_token":"close_token","action":"close_youth_mode","expires_at":"2026-08-20T09:05:00Z"}` |
 | `GET /v1/im/security/realname` | Query only | `{"status":"unverified","can_submit":true}` |
 | `POST /v1/im/security/realname/submissions` | `{"name":"张三","id_type":"cn_id","id_number":"110101199001011234"}` | `{"submission_id":"rn_1","status":"pending","can_submit":false}` |
-| `POST /v1/im/security/realname/appeals` 待实现 | `{"reason":"证件变更","description":"需要更正实名信息","action_token":"action_token"}` | `{"appeal_id":"rna_1","status":"pending","submitted_at":"2026-08-20T09:00:00Z"}` |
+| `POST /v1/im/security/realname/appeals` | `{"reason":"证件变更需要更正实名信息","attachments":["file_1"]}` | `{"appeal_id":"rna_1","reason":"...","attachments":["file_1"],"status":"pending"}`；当前无需二次身份验证（如后续启用，将复用 1.7 的 action_token 机制并在此处更新） |
 | `PUT /v1/im/devices/{device_id}/push-token` | `{"provider":"jpush","token":"registration_id","platform":"android","app_version":"1.0.0","push_env":"test","sdk_version":"5.0.0","notification_permission":"granted"}` | `{"device_id":"device_1","provider":"jpush","platform":"android","app_version":"1.0.0","updated_at":"2026-08-20T09:00:00Z"}` |
 | `DELETE /v1/im/security/sessions/{session_id}` 待实现 | Header `X-Action-Token: action_token` | `{"session_id":"sess_1","revoked":true}` |
+| `POST /v1/im/me/password` | `{"old_password":"OldPass123","new_password":"NewPass123"}` | `{"status":"ok"}`；旧密码错误返回 HTTP `401`：`{"code":30001,"reason":"AUTH_REQUIRED","message":"invalid credentials"}`；新密码不满足策略返回 HTTP `400`：`{"code":30040,"reason":"PASSWORD_POLICY_VIOLATION"}` |
+| `POST /v1/im/security/challenges` 注销账号发码 | Header `Idempotency-Key`；Body `{"scene":"delete_account","channel":"sms"}` | `{"challenge_id":"sec_chg_9","phone_mask":"+861****000","expires_in_seconds":300,"resend_after_seconds":60}` |
+| `POST /v1/im/security/challenges/{id}/verify` 注销账号验证 | `{"code":"123456"}` | `{"action_token":"del_token","action":"delete_account","expires_at":"2026-08-20T09:05:00Z"}` |
+| `POST /v1/im/me/deletion` | Header `X-Action-Token: del_token`；Body `{}` | `{"status":"ok"}` |
+
+#### 10.22.2 账号安全：修改密码与注销账号
+
+**修改密码 `POST /v1/im/me/password`（已实现）：**
+
+- 已登录（Bearer）用户提交 `old_password`、`new_password`；两者必填，缺一返回 `400 MALFORMED_REQUEST`。
+- 服务端先用旧密码走 `basic` 认证校验，失败返回 HTTP `401`：`{"code":30001,"reason":"AUTH_REQUIRED","message":"invalid credentials"}`，不泄露账号状态。
+- 新密码不满足密码策略返回 HTTP `400`：`{"code":30040,"reason":"PASSWORD_POLICY_VIOLATION"}`。
+- 成功后服务端递增 `auth_version` 并撤销该用户全部在线 Session（广播 `password_changed`）；包括当前请求在内的所有旧 Token 全部失效，客户端收到成功响应后必须清理本租户凭证并跳转登录页。
+
+**注销账号 `POST /v1/im/me/deletion`（已实现）：**
+
+- 两步挑战复用 1.7 敏感操作基建：`POST /v1/im/security/challenges`（Body `{"scene":"delete_account","channel":"sms"}`，发码到账号绑定手机号）→ `POST /v1/im/security/challenges/{id}/verify`（返回一次性 `action_token`）→ `POST /v1/im/me/deletion`（Header `X-Action-Token` 携带）。
+- 服务端配置 `permanent_accounts=true` 时拒绝注销：HTTP `403` `{"code":30040,"reason":"FORBIDDEN","message":"account deletion is disabled"}`。
+- 执行成功为**软删除**：撤销全部认证记录（含登录密码）、踢出所有在线 Session（`reason=user_deleted`）、退出并停用其拥有的群与 P2P 会话、向关注该用户的好友下发 `gone` 在线状态；账号不再可登录。客户端收到成功响应后清理本地数据并返回企业入口。
+- 挑战阶段限流与错误码同 1.7（`VERIFICATION_RATE_LIMITED`、`CHALLENGE_EXPIRED`、`CODE_INVALID`、`TOO_MANY_ATTEMPTS`）；action token 缺失/无效返回 HTTP `403` `{"code":30042,"reason":"ACTION_TOKEN_INVALID"}`。
 
 ## 11. 反诈安全、举报与意见反馈