Move storage backend configuration from startup YAML to system_config-backed runtime configuration. Add local, S3-compatible, R2, MinIO, OSS, and WebDAV backend support.
Add a storage migration async task using the existing task dispatch framework. Migration target config is carried in task payload, and maintenance mode is derived from task execution state.
Split upload file management and storage operations, add the admin storage configuration tab, and update migrations and Swagger docs.
- Add access_mode column to w_uploads table (0 = private, 1 = public) and initialize data in a single migration script
- Enforce strict ownership check for private files during download
- Allow public files to follow whitelisted public-access rules
- Default access_mode to public for avatars and private for generic uploads
- Update frontend service to support optional accessMode parameter
ryan