Function cmd_index 

pub fn cmd_index(
    project_path: &str,
    force: bool,
    config: &SeekrConfig,
    json_output: bool,
) -> Result<(), SeekrError>

Execute the seekr-code index command.

Scans the project directory, parses source files into chunks, generates embeddings, and builds + persists the search index. Supports incremental indexing: only re-processes changed files unless --force is specified.