Function process_file 

async fn process_file(
    path: &Path,
    store: &Arc<dyn VectorStore>,
    extractors: &Arc<ExtractorRegistry>,
    chunkers: &Arc<ChunkerRegistry>,
    embedder: &Arc<EmbedderPool>,
    config: &IndexerConfig,
) -> Result<u32>

Process a file through the full pipeline: extract → chunk → embed → store.