Add an optional comma-separated `ids` query parameter to GET /api/jobs so a
caller can poll a known set of jobs in a single request instead of one call
per job. The filter narrows the result to the requested job ids and composes
with the existing status / workflow_id filters; an absent or empty `ids` means
no filter.
The handler caps the request at 100 ids (checked before validation) and
validates each id with the existing validate_job_id helper, returning HTTP 400
on overflow or a malformed id. get_all_jobs gains an optional ids argument that
narrows the normalized job list by id.
Adds unit coverage for the filter logic and the endpoint's validation contract.
