Reconcile docs/federation/TASKS.md against main (0.0.48): mark FED-M3-01
(#506), -02 (#505), -03 (#509), -08 (#508) done; mark dependency-clear
FED-M3-04/07/09 in-progress (dispatched to coder lane). Adds a dated
backlog-sync note recording merges, dispatch, and the remaining DAG.
Backlog was stale (all M3 marked not-started) despite four merged PRs,
which masked three ready cards while the coder lane sat idle.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>