Function validate_code_map_target 

pub fn validate_code_map_target(
    workspace_root: &Path,
    thread_id: &str,
    requested_path: &Path,
    resolved_path: &Path,
) -> Result<bool>

Enforce the session boundary for an explicit CodeMap path.

Returns true only for a helper in the active session. A request spelling a temporary path that resolves elsewhere (for example through a symlink) is rejected instead of being misclassified as canonical source.