fix(admin-lists): force full fetch so persisted lastSeen can't hide current list

fetchLatestListEvent fetched admin lists via fetchListIncrementally without an
explicit `since`, so it relied on the persisted per-relay lastSeen. Admin lists
are replaceable events with a single current version whose created_at does not
advance, so once lastSeen == that created_at, every later load queries
since=lastSeen+1 and the relay returns nothing — perpetually hiding the current
list and dropping admin lists whenever the local cache is absent.

Pass since: 0 to force a full fetch of the (tiny) current event each time. Other
list callers anchor an explicit since to their own cached state; admin lists
have no comparable per-list timestamp, so always re-fetching current is both
correct and cheap.

Adds tests/nostr/relayBatchFetcherReplaceable.test.mjs documenting the
replaceable-event since-gate at the fetcher boundary: relying on persisted
lastSeen hides the current event; since: 0 returns it.

Co-Authored-By: Claude Opus 4.8 <[email protected]>

js/adminListStore.js

@@ -576,6 +576,11 @@ async function fetchLatestListEvent(filter, contextLabel = "admin-list") {
           pubkey,
           dTag,
           relayUrls: relays,
+          // Force a full fetch: admin lists are replaceable events whose
+          // created_at doesn't advance, so a persisted lastSeen would gate
+          // since=lastSeen+1 and perpetually hide the current event across
+          // reloads. See tests/nostr/relayBatchFetcherReplaceable.test.mjs.
+          since: 0,
         }),
         timeoutPromise,
       ]);