[feature] Infinite loop flow control

Remaining item from #1057 (flow controls / task dispatchers): **infinite loop** is not done.

Current state:
- The `loop` task dispatcher has a `loopForever` parameter (documented in `docs/content/docs/reference/flow-controls/loop_v1.mdx`) and a companion `loopBreak` dispatcher, but the infinite-loop checklist item from #1057 is not considered complete by this.

Scope: implement proper infinite loop flow control support (and document it in `docs/content/docs/reference/flow-controls/`).