Function batch_fetch 

pub async fn batch_fetch(
    refs: &[Ref],
    profile: &CapabilityProfile,
    ctx: &FetchContext,
    store: &dyn Store,
    store_root: &Utf8Path,
) -> Result<BatchOutcome, FetchError>

Iterate over refs through fetch_paper, collecting one BatchResultEntry per ref.

Cap: caller must supply at most MAX_BATCH_REFS refs; otherwise the function returns Err(FetchError::TooManyRefs { got, max }) before any fetch is attempted. The cap mirrors the CLI’s commands::batch enforcement (MCP_BATCH_MAX_SIZE).

Concurrency: Slice 2 dispatches refs serially through fetch_paper. The CLI’s existing commands::batch::run_with_options keeps its bounded-concurrency JoinSet+semaphore path for backward compatibility; the MCP server uses this serial loop because the MCP tool boundary already serializes calls per session.

Session bookkeeping: this function does NOT emit SessionStart / SessionEnd rows — that is the caller’s responsibility.