feat(cache,worker): overhaul cache layer and add generation task lease recovery

- shared/cache: add Options/L1/async/metrics/prefix decorators, multi-key ops, Redis pool tuning, and JSON readthrough metrics
- worker-generate: claim tasks via DB lease + heartbeat, requeue stale queued tasks, expire dead leases with refund/cache invalidation
- tenant: version article cache keys so worker recovery invalidations propagate cleanly
- shared/config: expand Redis (pool/timeouts/TLS) and Generation (lease/recovery) configs with defaults

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

server/internal/shared/repository/redis/redis.go

@@ -20,8 +20,17 @@ func NewClient(ctx context.Context, cfg config.RedisConfig) (*goredis.Client, er
 
 func NewLazyClient(cfg config.RedisConfig) *goredis.Client {
 	client := goredis.NewClient(&goredis.Options{
-		Addr: cfg.Addr,
-		DB:   cfg.DB,
+		Addr:         cfg.Addr,
+		Password:     cfg.Password,
+		DB:           cfg.DB,
+		DialTimeout:  cfg.DialTimeout,
+		ReadTimeout:  cfg.ReadTimeout,
+		WriteTimeout: cfg.WriteTimeout,
+		PoolSize:     cfg.PoolSize,
+		MinIdleConns: cfg.MinIdleConns,
+		MaxRetries:   cfg.MaxRetries,
+		PoolTimeout:  cfg.PoolTimeout,
+		TLSConfig:    cfg.TLSConfig(),
 	})
 	return client
 }