Add change password feature to settings page

- Add PUT /api/me/password endpoint in backend
- Add changePassword API function in frontend
- Add change password form UI in SettingsPanel
- Add i18n translations for change password (zh/en)
- Fix TypeScript type error in i18n context

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

backend_rust/src/api/me.rs

@@ -5,6 +5,7 @@ use sea_orm::{ActiveModelTrait, EntityTrait, Set};
 use serde::{Deserialize, Serialize};
 use std::io::Write;
 use uuid::Uuid;
+use bcrypt;
 
 use crate::app_data::AppData;
 use crate::entity::user;
@@ -33,6 +34,13 @@ pub struct UpdateSettingsRequest {
     pub bark_enabled: Option<bool>,
 }
 
+#[derive(Debug, Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub struct ChangePasswordRequest {
+    pub current_password: String,
+    pub new_password: String,
+}
+
 #[get("")]
 async fn get_me(
     app_data: web::Data<AppData>,
@@ -208,9 +216,46 @@ async fn upload_avatar(
     Ok(HttpResponse::Ok().json(UploadAvatarResponse { avatar_url }))
 }
 
+#[put("/password")]
+async fn change_password(
+    app_data: web::Data<AppData>,
+    auth: AuthUser,
+    body: web::Json<ChangePasswordRequest>,
+) -> Result<impl Responder, ApiError> {
+    if body.new_password.len() < 6 {
+        return Err(ApiError::BadRequest("New password must be at least 6 characters".to_string()));
+    }
+
+    let user = user::Entity::find_by_id(auth.user_id)
+        .one(&app_data.db)
+        .await?
+        .ok_or_else(|| ApiError::NotFound("User not found".to_string()))?;
+
+    // Verify current password
+    let valid = bcrypt::verify(&body.current_password, &user.password_hash)
+        .map_err(|_| ApiError::Internal("Password verification failed".to_string()))?;
+
+    if !valid {
+        return Err(ApiError::BadRequest("Current password is incorrect".to_string()));
+    }
+
+    // Hash new password
+    let new_password_hash = bcrypt::hash(&body.new_password, 10)
+        .map_err(|_| ApiError::Internal("Password hashing failed".to_string()))?;
+
+    // Update password
+    let mut active: user::ActiveModel = user.into();
+    active.password_hash = Set(new_password_hash);
+    active.updated_at = Set(chrono::Utc::now().fixed_offset());
+    active.update(&app_data.db).await?;
+
+    Ok(HttpResponse::Ok().json(serde_json::json!({"success": true})))
+}
+
 pub fn routes() -> Scope {
     web::scope("/api/me")
         .service(get_me)
         .service(update_settings)
         .service(upload_avatar)
+        .service(change_password)
 }