feat: initial sharing impl

apps/backend/internal/virtualfs/scoped_router.go

@@ -0,0 +1,13 @@
+package virtualfs
+
+import "github.com/gofiber/fiber/v2"
+
+// ScopedRouter is a router that guarantees reqctx.VFSAccessScope(c)
+// returns a valid *Scope for all registered routes.
+//
+// This is the base type for routers that provide VFS access scope.
+// More specific router types (like account.ScopedRouter) may embed this
+// to provide additional guarantees.
+type ScopedRouter struct {
+	fiber.Router
+}