feat: Use dynamic library linking for Linux/macOS to fix debug build heap corruption

[Sqhh99]

Summary

This PR:

1. Resolves the corrupted size vs. prev_size heap corruption error on Linux debug builds
2. Fixes the release workflow to correctly build and publish SDK artifacts

Problem

Debug-built examples crash on Linux:

corrupted size vs. prev_size
Aborted (core dumped)

Root Cause: Statically linking liblivekit_ffi.a mixes Debug C++ code with Release libwebrtc code, causing ABI incompatibilities and heap corruption.

Solution

Use dynamic library linking (.so/.dylib) on Linux/macOS, matching the Windows DLL architecture.

Key Changes:

• Dramatically Reduced Size: SDK package reduced from ~400MB to ~40MB (release builds only; users can build debug locally or this can be added later)
• ABI Isolation: Rust/libwebrtc code runs in its own address space, preventing Debug/Release mixing
• Independent Memory Management: Each library uses its own allocator
• Consistent Architecture: Same approach across Windows, Linux, and macOS

Note: When linking, liblivekit.a must be linked before liblivekit_ffi.so:

target_link_libraries(your_app PRIVATE livekit livekit_ffi)

SDK Release Structure

livekit-sdk-linux-x64-{version}/
├── bin/                              # Example executables + runtime dependencies
│   ├── SimpleRoom, SimpleRpc, SimpleDataStream
│   ├── liblivekit_ffi.so, libSDL3.so.0
│   └── data/
├── include/livekit/                  # Public headers
└── lib/
    ├── liblivekit.a                  # Static C++ wrapper
    └── liblivekit_ffi.so             # Rust FFI shared library

livekit-sdk-macos-arm64-{version}/    # Similar structure with .dylib
livekit-sdk-windows-x64-{version}/    # Similar structure with .dll

Changed Files

File	Lines	Description
.github/workflows/builds.yml	2	Minor CI path fix
.github/workflows/make-release.yml	107	Include bin/ directory with examples; fix double-compression; use versioned artifact names
CMakeLists.txt	106	Use SHARED IMPORTED for livekit_ffi on Unix; add RPATH settings; copy .so/.dylib to output
DEPENDENCIES.md	18	Update for dynamic library usage and deployment requirements
README.md	4	Add .so/.dylib deployment note
README_BUILD.md	37	Update build output structure documentation
examples/CMakeLists.txt	70	Add RPATH for examples; copy SDL3 shared library; create SONAME symlink on Linux
examples/cmake/sdl3.cmake	40	SDL3 FetchContent configuration updates

Testing

Platform	Debug	Release
Linux x64	✅	✅
macOS arm64	-	✅
Windows x64	✅	✅