Add HS256 JWT authentication to both HTTP and gRPC servers using
Kratos jwt middleware with selector to skip auth for public share
endpoints (GetShareInfo, DownloadShare). Wire DI updated to inject
conf.Auth into server constructors.
Add new framework dependencies needed for the Gin-to-Kratos migration:
- go-kratos/kratos/v2 (HTTP/gRPC transport, config, middleware, JWT auth)
- google/wire (compile-time dependency injection)
- ThreeDotsLabs/watermill + watermill-sql/v2 (event-driven CQRS)
- gorm.io/gorm + gorm.io/driver/postgres (PostgreSQL ORM)
The old Gin/Swagger deps remain as direct deps since existing code still
imports them. They will be removed in later migration tasks when code is
rewritten. Blank imports in internal/deps.go ensure go mod tidy keeps
the new deps until actual code imports them directly.
