Tests for the link model + lint/format pass

test_remote.py: link URL parsing, RAM-only offer mint/spend/expiry,
pushed-domain application (accept/idempotence/removal/local conflict/
auth-host collision), admin link lifecycle (offer, scope, revoke) and
uplink list/unlink, remote-write rejection on the domains API, live feed
scope mutation.

test_satellite_e2e.py: real registration handshake over TCP (key material
identical on both sides, duplicate and bad-URL rejections), established
link reconnect, revocation unlinking the satellite, live scope shrink
stopping the feed, domain conflicts reported upstream.

Also: ruff format drift fixes in startupbox/test_cli.

tests/test_cli.py

@@ -324,7 +324,9 @@ def test_migrate_merges_kantadb_into_existing_database(run_cli, tmp_path):
 def test_migrate_merge_label_combines_rp_ids(run_cli, tmp_path):
     """A multi-domain source merges in one transaction, rp-ids slash-joined."""
     run_cli("init", "company.com")
-    src = write_kantadb(tmp_path, {"one.com": "One", "two.com": "Two"}, name="x.kantadb")
+    src = write_kantadb(
+        tmp_path, {"one.com": "One", "two.com": "Two"}, name="x.kantadb"
+    )
 
     run_cli("migrate", str(src))