New package internal/batch holding the runner core with no workers yet (task 03
adds them; until then every job stays queued, so a queued job counts as live for
the caps). batch.go defines the public surface: Options/Target/Result/TargetError,
FetchFunc, Job/TargetStatus, Hooks and Config with its defaults (TTL 24h, 32
targets/job, 1 job/caller, 8 total, worker clamped to 2, 64 MiB, 2 s / 10 m retry).
Submit runs in the given order: empty → ErrNoTargets; idempotency via hex SHA-256
of `c.Name + NUL + json.Marshal(targets)` (a live BatchJobByIDem hit returns the id
reused, touching no caps); then TargetsPerJob / JobsPerCaller / JobsTotal; then it
stores the job queued (random 16-byte hex id, CreatedAt = Lease = now) and its
targets (pending, Options = json of t.Options) before returning. The submitting
caller is held in memory keyed by job id, never persisted (jobs never resume after
a restart). Status maps the rows and decodes Result from the result column without
writing; Touch moves the lease; Cancel sets a queued job cancelled at once and
leaves its targets pending; Close is idempotent. Store errors are Warn-logged with
the job id, never a URL or host.
Co-Authored-By: ornith-1.5-35b-a3b <ornith-1.5-35b-a3b@llama.cpp.invalid>
