Parallel teach lifecycle — source snapshot 2026-09-12

Source-only prerelease of matching core, node, and CLI changes. Core exposes an operator-configurable active-jobs-per-key limit; node enforces it with a 70-job concurrent admission regression test; CLI adds ainize teach parallel, using ain-js for finalized per-job status paths confirmed by an independent validator. The default per-key limit remains 2. GPU trainer slots are unchanged: 70 admitted/queued jobs do not prove 70 simultaneous GPU training processes. Real 70-job on-chain end-to-end evidence is not claimed by this source release. This is not an npm package publication. CLI usage: https://github.com/ainblockchain/ainize-cli/blob/teach-parallel-20260912/docs/parallel-teach.md