librtmp2 0.1.0

First tagged pre-release. librtmp2 is a Rust crate (built via Cargo as
cdylib/staticlib/lib) exposing both an idiomatic Rust API and an
FFI-compatible extern "C" layer for consumption from C, Go, Python, PHP,
and others.

Added

• TLS / RTMPS support via OpenSSL, enabled by default through the tls
  Cargo feature (cargo build --no-default-features for a zero-dependency,
  plaintext-only build)
• Transport abstraction shared by plaintext RTMP and TLS so the layers above
  never branch on the wire type
• Server-side TLS termination and client-side rtmps:// connect with SNI
  and certificate verification
• lrtmp2_tls_supported() runtime capability check
• Legacy RTMP protocol support (handshake, chunk, message, AMF0)
• Enhanced RTMP v1 support (ExVideo/ExAudio headers, FourCC registry, HDR/colorInfo)
• Enhanced RTMP v2 support (capsEx, reconnect, multitrack, ModEx)
• Full server API with callbacks (on_connect, on_publish, on_play, on_frame, on_close)
• Full client API with publish/play flows
• Frame API supporting audio, video, script, and metadata types
• H.264, H.265, AV1, and legacy video codec support
• AAC, Opus, MP3, G.711 audio codec support
• Example programs: minimal_server, minimal_client, play_pull, ffmpeg_ingest
• Inline unit tests throughout src/, an end-to-end loopback integration
  test (tests/server_client_loopback.rs), and interop shell scripts
  (tests/interop/)
• ABI baseline tooling (scripts/abi-baseline.sh) for 0.x compatibility checks
• Automated ABI compliance checks in CI (cargo-semver-checks via .github/workflows/abi-check.yml)

Security

• Bounds-checked parsers for all network-provided length fields
• Constant-time RNG for handshake
• Safe handling of unknown E-RTMP v2 ModEx types (degrades to NOP, not panic)

Documentation

• CLAUDE.md with build commands and architecture guide
• docs/abi-policy.md with ABI compliance checklist
• Protocol mapping documents for legacy, E-RTMP v1, and E-RTMP v2
• CONTRIBUTING.md guidelines