feat(redis): keep services running when Redis is unreachable

Add a lazy Redis client constructor and an in-memory fallback for the
refresh-session store, plus tenant-api and ops-api bootstrap that warns
and continues with the lazy client instead of failing. Refresh and
blacklist operations now silently fall back to the in-memory store while
Redis is down so existing sessions stay valid until it recovers.

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

server/internal/bootstrap/bootstrap.go

@@ -90,9 +90,8 @@ func New(configPath string) (*App, error) {
 
 	rdb, err := redis.NewClient(ctx, cfg.Redis)
 	if err != nil {
-		pool.Close()
-		monitoringPool.Close()
-		return nil, fmt.Errorf("init redis: %w", err)
+		logger.Warn("redis unavailable during startup; continuing with degraded auth/cache fallback", zap.Error(err))
+		rdb = redis.NewLazyClient(cfg.Redis)
 	}
 
 	mqClient, err := rabbitmq.New(ctx, cfg.RabbitMQ)