[zhangzhenghao]

Summary

• Add a Debian 13 C++ development container with FFmpeg installed via apt in the Dockerfile.
• Install Rust, Python and Node.js 22 through Dev Container Features with resolved feature versions locked.
• Keep CMake and GCC supplied by the C++ base image; no separate features for them.
• Initialize recursive Git submodules on container creation.
• No README changes.

Validation

• Dev Containers CLI resolves the Dockerfile-based configuration and all three features.
• git diff --cached --check passes.
• Full container build and runtime tests have not been verified; an earlier local build attempt ran out of host disk space.