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>

frontend/src/ui/components/CanvasAnnotations/index.tsx

@@ -0,0 +1,31 @@
+"use client";
+
+import type { CanvasViewport } from "@/domain/design";
+import type { CanvasAnnotation } from "@/ui/components/PromptComposer";
+
+export function CanvasAnnotations({
+  annotations,
+  viewport
+}: {
+  annotations: CanvasAnnotation[];
+  viewport: CanvasViewport;
+}) {
+  if (annotations.length === 0) return null;
+
+  return (
+    <div className="canvas-annotation-layer" aria-hidden="true">
+      {annotations.map((annotation) => (
+        <span
+          key={annotation.id}
+          className="canvas-annotation-marker"
+          style={{
+            left: viewport.x + annotation.x * viewport.k,
+            top: viewport.y + annotation.y * viewport.k
+          }}
+        >
+          <b>{annotation.index}</b>
+        </span>
+      ))}
+    </div>
+  );
+}