feat: rename qiniu to oss, add admin upload proxy with thumbnail, add dev-login

- Rename all QINIU_* config/code/docs to OSS_* to match actual Alibaba Cloud OSS
- Refactor upload module from internal/common/qiniu to internal/common/upload
- Add backend proxy upload endpoint (POST /api/admin/marketing/upload) to avoid CORS
- Auto-generate compressed thumbnail (800px, JPEG 80%) on admin image upload
- Add dev-login endpoint (POST /api/v1/auth/dev-login) for H5 debugging
- Add imageutil package for server-side image resizing

Made-with: Cursor

.env.example

@@ -46,25 +46,25 @@ ADMIN_API_TOKEN=replace-with-strong-random-token
 ADMIN_DEFAULT_USERNAME=admin
 ADMIN_DEFAULT_PASSWORD=admin123
 
-# 七牛直传配置（Kodo）
-QINIU_ACCESS_KEY=replace-with-access-key
-QINIU_SECRET_KEY=replace-with-secret-key
-QINIU_BUCKET=replace-with-bucket
-# 上传地址：可保持默认（自动调度），也可以配置具体 Region 的 up 域名
-QINIU_UPLOAD_URL=https://upload.qiniup.com
-# CDN 域名（可选）：用于拼接最终访问地址，例如 https://cdn.example.com
-QINIU_CDN_DOMAIN=
+# 阿里云 OSS 直传配置
+OSS_ACCESS_KEY=replace-with-access-key
+OSS_SECRET_KEY=replace-with-secret-key
+OSS_BUCKET=replace-with-bucket
+# 上传地址（可选）：OSS 时自动根据 endpoint 计算，留空即可
+OSS_UPLOAD_URL=
+# CDN 域名：阿里云 OSS endpoint，例如 oss-cn-beijing.aliyuncs.com
+OSS_CDN_DOMAIN=
 # 上传 key 前缀（可选）
-QINIU_KEY_PREFIX=uploads/
-# token 有效期（秒）
-QINIU_TOKEN_EXPIRE_SECONDS=300
-# 上传回调地址（可选）：配置后，七牛上传成功会回调该地址
-# 示例: https://api.example.com/api/v1/common/upload/qiniu/callback
-QINIU_CALLBACK_URL=
+OSS_KEY_PREFIX=uploads/
+# 凭证有效期（秒）
+OSS_TOKEN_EXPIRE_SECONDS=300
+# 上传回调地址（可选）：上传成功后回调该地址
+# 示例: https://api.example.com/api/v1/common/upload/oss/callback
+OSS_CALLBACK_URL=
 # 回调内容模板（可选）
-QINIU_CALLBACK_BODY=key=$(key)&hash=$(etag)&fsize=$(fsize)&mimeType=$(mimeType)
+OSS_CALLBACK_BODY=key=$(key)&hash=$(etag)&fsize=$(fsize)&mimeType=$(mimeType)
 # 回调内容类型（可选）
-QINIU_CALLBACK_BODY_TYPE=application/x-www-form-urlencoded
+OSS_CALLBACK_BODY_TYPE=application/x-www-form-urlencoded
 
 # 微信公众号（网页授权 OAuth2）
 WECHAT_OA_APP_ID=replace-with-oa-appid