need an archipelago restart
Previously the server checked `fips0` once at startup; if the
interface wasn't up (pre-onboarding, or post-onboarding before the
user clicked Activate FIPS), the peer listener never bound and stayed
unreachable until the next archipelago restart.
Replaced with a `peer_late_bind_loop` background task: polls every
30s for an fd00::/8 address on `fips0` and binds the listener the
moment one appears. First tick fires immediately so the hot path —
fips0 already up at startup — is still zero-cost. Cancellation
cascades through the same `tokio::sync::watch` channel the main
listener uses.
Side effects:
- main.rs no longer computes peer_addr eagerly; dropped the unused
param from serve_with_shutdown.
- FipsTransport::is_available already caches the service probe so
the 30s poll doesn't thrash systemctl.
Covers task #21. Unblocks the first-boot + onboarding flow for
fresh ISO installs on .253.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
84943aaa04