feat(bag-writer): Use WriterConfig options for compression and chunk size

[zhexuany]

Overview

The BagFormat::create_writer() method currently ignores the WriterConfig parameter and always creates a writer with default settings.

Current State

pub fn create_writer<P: AsRef<Path>>(
    path: P,
    _config: &crate::io::writer::WriterConfig,
) -> Result<Box<dyn crate::io::traits::FormatWriter>> {
    // For now, we create a simple writer
    // TODO: Use config options for compression, chunk size, etc.
    let writer = BagWriter::create(path)?;
    Ok(Box::new(writer))
}

Desired Behavior

Use the WriterConfig to configure:

• Compression type: bz2, lz4, none
• Chunk size: Size of each chunk (default: 768KB)
• Chunk threshold: Messages per chunk before splitting

Example Implementation

pub fn create_writer<P: AsRef<Path>>(
    path: P,
    config: &crate::io::writer::WriterConfig,
) -> Result<Box<dyn crate::io::traits::FormatWriter>> {
    let compression = config.compression.as_deref().unwrap_or("bz2");
    let chunk_size = config.chunk_size.unwrap_or(768 * 1024);
    
    let writer = BagWriter::create_with_options(path, compression, chunk_size)?;
    Ok(Box::new(writer))
}

Files to Modify

• src/io/formats/bag/parallel.rs - Update create_writer() method
• src/io/formats/bag/writer.rs - Add create_with_options() method

Acceptance Criteria

• Compression option is respected ("bz2", "lz4", "none")
• Chunk size option is respected
• Default values match historical ROS1 bag behavior
• Tests verify each configuration option
• Documentation is updated

Related Code

• Location: src/io/formats/bag/parallel.rs:59
• See also: WriterConfig definition in src/io/writer/mod.rs