FlowDrop 2.1.0 First minor of the 2.x line. Adds the human-in-the-loop confirmation gate: side-effecting nodes can require operator approval before executing, on both the graph plane and the tool plane. Approval is argument-bound and consume-once; decline routes down the node's normal error channel and never fails the run. Non-breaking by construction: the fail-closed derived default applies only to node types that have not chosen, and a post-update grandfathers existing undecided side-effecting types to an explicit FALSE — nothing that ran unattended before 2.1.0 pauses after it. No @api surface changes; every class added in this release is @internal, so the 2.0.0 freeze carries forward. Gate at this tag: phpcs, phpstan level 8 (zero production baseline), spec coverage (registry and bindings agree, RT-GATE-1..7 pinned) and the full phpunit-parallel suite (329 classes) green. Playwright e2e NOT run — unchanged editor bundle, same status as the 2.0.0 tag.