Initial commit: img-infinite-canvas AI design workbench MVP

Moteva-style AI design workbench replica. Home prompt creates a project;
the project page provides an infinite canvas with node drag, zoom/pan,
a design chat panel, history replay, image asset upload, and project
save/regenerate.

- Backend: go-zero, DDD layering, sqlc/pgx, optional PostgreSQL; memory
  or Redis cache; asynq job queue; MinIO/S3/R2/OSS object storage;
  sky-valley/pi agent runtime adapter.
- Frontend: Next.js App Router + Vite artifact build, TypeScript, i18n,
  shadcn/ui components, auth (OTP/Turnstile/Google/WeChat).
- Deploy: Docker Compose and k3s manifests.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

server/internal/infrastructure/objectstorage/url.go

@@ -0,0 +1,45 @@
+package objectstorage
+
+import (
+	"net/url"
+	"strings"
+)
+
+func objectKeyFromPublicURL(publicBase string, value string) (string, bool) {
+	value = strings.TrimSpace(value)
+	publicBase = strings.TrimRight(strings.TrimSpace(publicBase), "/")
+	if value == "" || publicBase == "" {
+		return "", false
+	}
+
+	if strings.HasPrefix(value, publicBase+"/") {
+		return unescapeObjectKey(strings.TrimPrefix(strings.Split(value, "?")[0], publicBase+"/"))
+	}
+
+	parsedValue, err := url.Parse(value)
+	if err != nil {
+		return "", false
+	}
+	parsedBase, err := url.Parse(publicBase)
+	if err != nil {
+		return "", false
+	}
+	basePath := strings.TrimRight(parsedBase.EscapedPath(), "/")
+	valuePath := parsedValue.EscapedPath()
+	if basePath == "" || !strings.HasPrefix(valuePath, basePath+"/") {
+		return "", false
+	}
+	return unescapeObjectKey(strings.TrimPrefix(valuePath, basePath+"/"))
+}
+
+func unescapeObjectKey(value string) (string, bool) {
+	value = strings.TrimLeft(strings.TrimSpace(value), "/")
+	if value == "" {
+		return "", false
+	}
+	objectKey, err := url.PathUnescape(value)
+	if err != nil {
+		return "", false
+	}
+	return objectKey, objectKey != ""
+}