feat: add upload policies, daily limits, and storage quotas

- Add environment variables to configure anonymous uploads, daily upload caps, and default user storage limits.
- Update config loader to parse and validate the new settings.
- Implement backend logic to track daily usage and active storage per user.
- Update README and `.env.example` to document the new settings and admin panels.

scripts/env/dev.env.example

@@ -10,6 +10,12 @@ WARPBOX_CLEANUP_EVERY=1h
 WARPBOX_THUMBNAIL_ENABLED=true
 WARPBOX_THUMBNAIL_EVERY=1m
 WARPBOX_MAX_UPLOAD_SIZE_MB=16384
+WARPBOX_ANONYMOUS_UPLOADS_ENABLED=true
+WARPBOX_ANONYMOUS_MAX_UPLOAD_MB=512
+WARPBOX_ANONYMOUS_DAILY_UPLOAD_MB=2048
+WARPBOX_USER_DAILY_UPLOAD_MB=8192
+WARPBOX_DEFAULT_USER_STORAGE_MB=51200
+WARPBOX_USAGE_RETENTION_DAYS=30
 WARPBOX_READ_TIMEOUT=15s
 WARPBOX_WRITE_TIMEOUT=60s
 WARPBOX_IDLE_TIMEOUT=120s