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/cache/store.go

@@ -0,0 +1,89 @@
+package cache
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"sync"
+	"time"
+)
+
+var ErrUnsupportedDriver = errors.New("unsupported cache driver")
+
+type Store interface {
+	Get(ctx context.Context, key string, target any) (bool, error)
+	Set(ctx context.Context, key string, value any, ttl time.Duration) error
+	Delete(ctx context.Context, key string) error
+}
+
+type memoryItem struct {
+	value     []byte
+	expiresAt time.Time
+}
+
+type MemoryStore struct {
+	mu    sync.RWMutex
+	items map[string]memoryItem
+}
+
+func NewMemoryStore() *MemoryStore {
+	return &MemoryStore{
+		items: make(map[string]memoryItem),
+	}
+}
+
+func (s *MemoryStore) Get(ctx context.Context, key string, target any) (bool, error) {
+	if err := ctx.Err(); err != nil {
+		return false, err
+	}
+
+	s.mu.RLock()
+	item, ok := s.items[key]
+	s.mu.RUnlock()
+	if !ok {
+		return false, nil
+	}
+	if !item.expiresAt.IsZero() && time.Now().After(item.expiresAt) {
+		s.mu.Lock()
+		delete(s.items, key)
+		s.mu.Unlock()
+		return false, nil
+	}
+
+	if err := json.Unmarshal(item.value, target); err != nil {
+		return false, err
+	}
+	return true, nil
+}
+
+func (s *MemoryStore) Set(ctx context.Context, key string, value any, ttl time.Duration) error {
+	if err := ctx.Err(); err != nil {
+		return err
+	}
+
+	data, err := json.Marshal(value)
+	if err != nil {
+		return err
+	}
+
+	var expiresAt time.Time
+	if ttl > 0 {
+		expiresAt = time.Now().Add(ttl)
+	}
+
+	s.mu.Lock()
+	s.items[key] = memoryItem{value: data, expiresAt: expiresAt}
+	s.mu.Unlock()
+	return nil
+}
+
+func (s *MemoryStore) Delete(ctx context.Context, key string) error {
+	if err := ctx.Err(); err != nil {
+		return err
+	}
+
+	s.mu.Lock()
+	delete(s.items, key)
+	s.mu.Unlock()
+	return nil
+}