v1.2.10

• breaking: qpipeline standard config field runner.keep_latest_ckp is replaced by runner.checkpoint.regular_latest_only
• feat: qpipeline regular checkpoints now default to keeping only the latest file unless runner.checkpoint.regular_latest_only: false
• feat: upgrade qexp v2 agent lifecycle to machine-scoped active / draining / idle semantics with state/agent.json as the single lifecycle source of truth
• feat: add formal qexp v2 lifecycle contracts for machine worksets, agent snapshots, and machine summary caches
• fix: prevent on-demand qexp agents from auto-exiting while the current machine still owns running task responsibility
• fix: stop cross-machine qexp status and orphan repair flows from misclassifying healthy remote agents via local PID probes
• docs: update qConfig docs and standard config generator output for runner.checkpoint.regular_latest_only
• docs: sync qexp manual and runtime/product specs with the final lifecycle contract and lifecycle-state observability rules
• test: add coverage for regular checkpoint latest-only rotation and config parsing
• test: add qexp v2 coverage for lifecycle state transitions, cross-machine observer behavior, orphan repair, and contract serialization