Add multiple NodeIKernel service interface files and tighten up method signatures and types across napcat-core. New interfaces added (e.g. NodeIKernelAVSDKService, NodeIKernelAddBuddyService, NodeIKernelBdhUploadService, NodeIKernelConfigMgrService, NodeIKernelDirectSessionService, NodeIKernelEmojiService, NodeIKernelFeedService, NodeIKernelFileBridgeClientService, NodeIKernelFileBridgeHostService, etc.). Updated existing interfaces with clearer parameter and return types, consistent spacing/semicolons, improved complex return shapes (AlbumService, CollectionService), listener methods, isNull checks, and many other method signature refinements (Avatar, Buddy, DbTools, ECDH, FileAssistant, FlashTransfer, GroupService, and more) to improve type safety and readability.
