fix(federation): self-heal also refreshes ap_timeline.url (heals dead links from a remote slug rename)
The inbound Update handler now refreshes url, but existing cached rows keep the old (dead) url
until re-fetched. selfHeal re-fetches cached notes but didn't update url either; now it does, and
SELFHEAL_VERSION 3->4 triggers a one-time re-sync at boot so already-cached renamed posts get the
correct link.
Co-Authored-By: Claude <noreply@…>