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/domain/design/image_size.go

@@ -0,0 +1,40 @@
+package design
+
+import (
+	"strconv"
+	"strings"
+)
+
+const (
+	DefaultGeneratedImageSize   = "1024x1024"
+	DefaultGeneratedImageWidth  = 1024
+	DefaultGeneratedImageHeight = 1024
+)
+
+func ParseImageSize(size string) (float64, float64, bool) {
+	size = strings.ToLower(strings.TrimSpace(size))
+	if size == "" {
+		return 0, 0, false
+	}
+	size = strings.NewReplacer(" ", "", "\t", "", "\n", "", "×", "x", "*", "x").Replace(size)
+	parts := strings.Split(size, "x")
+	if len(parts) != 2 {
+		return 0, 0, false
+	}
+	width, err := strconv.ParseFloat(parts[0], 64)
+	if err != nil || width <= 0 {
+		return 0, 0, false
+	}
+	height, err := strconv.ParseFloat(parts[1], 64)
+	if err != nil || height <= 0 {
+		return 0, 0, false
+	}
+	return width, height, true
+}
+
+func GeneratedImageDimensions(size string) (float64, float64) {
+	if width, height, ok := ParseImageSize(size); ok {
+		return width, height
+	}
+	return DefaultGeneratedImageWidth, DefaultGeneratedImageHeight
+}