Replace c.JSON(200, response.Err) and middleware gin.H bypasses with
response.Abort* helpers so errors flow through Gin Error chain and
ErrorHandlerMiddleware for OTel trace correlation.
Split oauth/sources.go into domain-focused files and decompose upload
into handler/filesrv/stats/task/cache/storage/util subpackages with a
root facade preserving existing import paths.
- Relocated generic HTTP response helpers (Response, OK, Err, etc.) from internal/util/ to a dedicated internal/common/response/ package.
- Renamed ResponseAny to Any to resolve revive stuttering warnings.
- Moved session building options and cookie headers logic from internal/util/ to internal/apps/oauth/.
- Removed all direct imports of Gin/Sessions/HTTP frameworks from internal/util/ to keep general utilities 100% pure.
- Regenerated Swagger API documentation via make swagger.
- All tests and make code-check compile and pass with 0 issues.
ryan