[1.0] Bound incomplete AND, batch and join input collections

Work can consume memory before a run exists. Limiting only scheduled runs does not bound the ArtifactCollector and other incomplete input groups.

Scope

• Bound held artifact references per subscription/group, including ordinary AND gates, batches and joins.
• Count references rather than only group objects; define explicit admission outcomes when collection capacity is exhausted.
• Preserve visibility, matching semantics and applicable expiration behavior; do not force all AND gates into correlation partitions.

Acceptance criteria

• Repeated A-only publication to consumes(A, B) retains at most the configured references and visibly throttles or rejects further admission.
• Batch/join cases also stay bounded; rejection does not falsely confirm a stored artifact as admitted to processing.
• Completion, expiry and explicit disposal release the relevant capacity without dropping accepted inputs silently.

Boundaries

Persisting enough receipts to show interrupted intake is a later dependent 1.0 task; restoring full collections after restart is post-1.0.

References

• Implementation dependencies: #440.
• src/flock/orchestrator/artifact_collector.py
• src/flock/orchestrator/scheduler.py
• src/flock/core/subscription.py

Read src/flock/orchestrator/artifact_collector.py, src/flock/orchestrator/scheduler.py, and src/flock/core/subscription.py, along with dependency #440. Trace how incomplete artifact groups are admitted and released for AND, batch, and join cases. Done means configured reference bounds, visible throttling or rejection, and correct release on completion, expiry, or disposal without falsely admitting rejected inputs.