Adds the Go/CGO receive path for Data.jobArray, mirroring task 5.3's
scheduler-side C implementation: rawJobArrayToModels() (pure-Go
base_jobid + i expansion), cJobArrayToModels() (CGO adapter sibling to
cJobToModel), dispatchJobArray() (dedup via the same store.Jobs.Has()
the ordinary Data_data_jobs path already writes through, single
confirmation log only when at least one element was newly
dispatched), and a new case C.Data_data_jobArray in handleDataset.
Elements route through OnJobUpdated, matching the ordinary single-job
push's own routing. The CGO boundary needed no changes -- both
C.xce_job_submit_t and C.Data_data_jobArray were already exposed from
prior tasks, including task 5.3b's extract_data() fix which this
receive path depends on identically to the scheduler's.
store.ArrayJobs (the array-level rollup aggregate) is deliberately
left unpopulated -- confirmed out of this spec's scope, deferred to a
future spec per requirements.md's Boundary Context.
Task 5.4 of job-array-single-wal-record (Requirements 6.2, 6.4, 6.5, 8.4).
Rongsong Shen
9e0d87fe50