Restore defaults for queue/executor_memory/executor_cores/num_executors
in prepare_submit_job, but require the caller to explicitly confirm
them. If any defaulted field is omitted, the route returns HTTP 400
listing the defaults and asks the caller to resubmit with explicit
values.
app_name remains required (no meaningful default). extra_args remains
optional.
Tests cover rejection of unconfirmed defaults and acceptance of
explicitly confirmed defaults.
Remove defaults from queue, executor_memory, executor_cores,
num_executors, and app_name in prepare_submit_job. All must now be
explicitly confirmed by the caller.
Also add extra_args to the PendingSubmission snapshot so users can
confirm non-conf spark-submit flags (e.g. --jars, --py-files) at
prepare time; confirm_submit_job passes them through to
build_spark_submit_command.
This is an intentional breaking change to the MCP tool contract:
callers can no longer rely on implicit defaults.