refactor(miniapp-runtime): Container abstraction for wujie integration

[Gaubee]

Summary

• Introduce ContainerManager interface following SOLID principles
• Implement IframeContainerManager (extracted from iframe-manager)
• Implement WujieContainerManager (using wujie library)
• Refactor launchApp to use container factory based on manifest.runtime

Architecture

src/services/miniapp-runtime/
├── container/
│   ├── types.ts              # ContainerManager, ContainerHandle interfaces
│   ├── iframe-container.ts   # IframeContainerManager implementation
│   ├── wujie-container.ts    # WujieContainerManager implementation
│   └── index.ts              # Factory: createContainer(type, options)
├── index.ts                  # launchApp uses factory
└── types.ts                  # MiniappInstance with containerHandle

SOLID Compliance

• S: Each container manager has single responsibility
• O: New runtime types can be added without modifying existing code
• L: Both managers implement same ContainerHandle interface
• I: ContainerHandle interface is minimal and focused
• D: launchApp depends on abstraction (ContainerManager), not concrete implementations

Testing

• pnpm typecheck passes
• Manual testing: dev server, iframe mode works
• Manual testing: build mode with wujie runtime

Breaking Changes

• MiniappInstance.iframeRef is deprecated, use containerHandle.element instead