fix(dm): ownership transfer divergence after back-and-forth — canonicalize ownerHomeInstance + normalize authority checks

Manual ownership transfers between two federated instances diverged because
`dm_channels.ownerHomeInstance` was stored as a BARE host (`orbit.ddns.net`)
for federated owners — via `transferGroupDmOwnership` copying `users.homeInstance`
verbatim — while `sourceInstance` always arrives as a full URL on the wire.
`processOwnershipTransferEvent` and `processMemberRemoveEvent` then compared the
two with strict equality and rejected legitimate inbound events as
`unauthorized_source`, keeping ownership permanently divergent across peers.
Live DB inspection on the two test instances confirmed both rows (nova + orbit)
had a BARE `owner_home_instance`, matching the bug report exactly.

Three compounding fixes:

1. Receiver authority checks now compare via `normalizeOriginForCompare` so
   legacy bare-vs-full rows accept legitimate transfers (and kicks).
2. New `canonicalizeHomeInstance` helper in `federationAuth.ts`; every write
   site that persists `ownerHomeInstance` (`transferGroupDmOwnership`, group DM
   creation, lazy federation in member-add, `processMemberAddEvent` bootstrap,
   `processOwnershipTransferEvent` receiver storage) routes through it. Full URL
   is the canonical storage form, matching how `sourceInstance` arrives.
3. `dm_owner_updated` WS event extended with optional `newOwnerHomeUserId` and
   `newOwnerHomeInstance` fields. Client `updateDmOwner` writes them when
   present and leaves existing values untouched otherwise (legacy-server safe).
   Without this, `getOwnerInstanceForDm` returned the previous owner's home
   after a successful WS broadcast, routing the next owner-only op to the wrong
   instance.

Coverage: new `federation.ownershipTransfer.test.ts` (7 receiver tests including
the headline bare-vs-full regression and the dedup replay guard); new bare-vs-full
case in `federation.kick.test.ts`; two new client-side cases in
`groupDm.ownerRouting.test.ts` covering both the extended-payload write path and
the legacy-server passthrough. Tests: 1053 server + 364 web, all green.

Specs updated: `dm-system.md` historical bugs + frontend handler table + WS
state-change events table; `federation.md` `ownership_transfer` receiver flow;
`websocket.md` event-fields table.

packages/web/src/hooks/useWebSocket.ts

@@ -1113,7 +1113,18 @@ function handleEvent(origin: string, event: ServerEvent): void {
     case 'dm_owner_updated': {
       if (!isHome && !activePeerOrigins.has(origin)) break;
       const { updateDmOwner } = useSpaceStore.getState();
-      updateDmOwner(event.dmChannelId, event.newOwnerId);
+      // Pass the federation routing fields so the DM's `ownerHomeInstance`
+      // stays in sync with the server. Without this, `getOwnerInstanceForDm`
+      // routes the next owner-only API call (rename, icon, kick, transfer)
+      // through the PREVIOUS owner's home instance and the receiving peer
+      // rejects it as `unauthorized_source`. Older servers omit these fields
+      // — the store leaves the existing values untouched in that case.
+      updateDmOwner(
+        event.dmChannelId,
+        event.newOwnerId,
+        event.newOwnerHomeUserId ?? undefined,
+        event.newOwnerHomeInstance ?? undefined,
+      );
       break;
     }