Initializes the Rust bridge. Returns false on web (no native bridge
exists there) or when the native library fails to load, so callers can
fall back to the pure-Dart parser deterministically.
Parse M3U content (entries + #EXTM3U header attributes) with the
synchronous, pure-Dart parser. This is the deterministic/test/web path
and never touches the native bridge — prefer parseM3uAsync when you
want Rust acceleration with automatic fallback.