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/svc/service_context_test.go

@@ -0,0 +1,42 @@
+package svc
+
+import (
+	"os"
+	"testing"
+
+	"img_infinite_canvas/internal/config"
+)
+
+func TestNewImageGeneratorReturnsNilWithoutAPIKey(t *testing.T) {
+	generator := newImageGenerator(config.Config{})
+	if generator != nil {
+		t.Fatal("expected nil image generator without API key")
+	}
+}
+
+func TestResolveImageAPIKeyUsesEnvBeforeConfig(t *testing.T) {
+	t.Setenv("TEST_GPT_IMAGE_KEY", "env-key")
+
+	key := resolveImageAPIKey(config.ImageGenerationConfig{
+		APIKeyEnv: "TEST_GPT_IMAGE_KEY",
+		APIKey:    "config-key",
+	})
+	if key != "env-key" {
+		t.Fatalf("expected env key, got %s", key)
+	}
+}
+
+func TestResolveImageAPIKeyFallsBackToConfig(t *testing.T) {
+	const envName = "TEST_GPT_IMAGE_KEY_EMPTY"
+	if err := os.Unsetenv(envName); err != nil {
+		t.Fatal(err)
+	}
+
+	key := resolveImageAPIKey(config.ImageGenerationConfig{
+		APIKeyEnv: envName,
+		APIKey:    "config-key",
+	})
+	if key != "config-key" {
+		t.Fatalf("expected config key, got %s", key)
+	}
+}