feat(links): Copy Lotus Link permalinks, in-app recognition, /home redirect for joined rooms, via= alias, OIDC deep-link redirect (#130)

matrix.to cannot target this deployment (Cinny adapter hard-codes
app.cinny.in; web-instance[] is Element-only, allowlisted), so add a
"Copy Lotus Link" next to every Copy Link (message menu, space header
menu, sidebar space tab) producing https://<this origin>/home/<room>/<event>
?viaServers=… via plugins/lotus-permalink.ts. Lotus links in messages are
rewritten to their matrix.to form inside the HTML parser so they render as
room/event mentions and navigate in place.

/home/<room> for a joined room that belongs to a space or Direct now
redirects to its own route (was a preview card with a View button; also
the form matrix.to → Cinny links use). ?via= is accepted as an alias of
?viaServers= (what the matrix.to Cinny adapter emits). A deep link
visited while logged out is now honoured after an OIDC login: the OIDC
callback reloads at the app root, which discarded the stored path — the
index loader consumes it via the shared takeAfterLoginPath().

Verified end-to-end with Playwright on a local Synapse: logged-out cold
link → login → lands on the event under the space route; menu copies the
expected link; a pasted Lotus link renders as a mention and jumps in
place; both space menus copy the space link.

Closes #130

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PPmy3tPq869XDW4njjVaKA

src/app/pages/client/home/RoomProvider.tsx

@@ -1,4 +1,4 @@
-import React, { ReactNode } from 'react';
+import React, { ReactNode, useEffect } from 'react';
 import { useParams } from 'react-router-dom';
 import { useSelectedRoom } from '../../../hooks/router/useSelectedRoom';
 import { IsDirectRoomProvider, RoomProvider } from '../../../hooks/useRoom';
@@ -6,6 +6,7 @@ import { useMatrixClient } from '../../../hooks/useMatrixClient';
 import { JoinBeforeNavigate } from '../../../features/join-before-navigate';
 import { useHomeRooms } from './useHomeRooms';
 import { useSearchParamsViaServers } from '../../../hooks/router/useSearchParamsViaServers';
+import { useRoomNavigate } from '../../../hooks/useRoomNavigate';
 
 export function HomeRouteRoomProvider({ children }: { children: ReactNode }) {
   const mx = useMatrixClient();
@@ -16,6 +17,21 @@ export function HomeRouteRoomProvider({ children }: { children: ReactNode }) {
   const roomId = useSelectedRoom();
   const room = mx.getRoom(roomId);
 
+  // [Gitea #130] `/home/<room>` is the universal permalink form (Lotus links,
+  // matrix.to → Cinny links). A room we are already in but that lives under a
+  // space or in Direct goes straight to its own route instead of a preview
+  // card with a "View" button.
+  const { navigateRoom, navigateSpace } = useRoomNavigate();
+  const joinedElsewhere =
+    !!room && room.getMyMembership() === 'join' && !rooms.includes(room.roomId);
+  useEffect(() => {
+    if (!joinedElsewhere || !room) return;
+    if (room.isSpaceRoom()) navigateSpace(room.roomId, { replace: true });
+    else navigateRoom(room.roomId, eventId, { replace: true });
+  }, [joinedElsewhere, room, eventId, navigateRoom, navigateSpace]);
+
+  if (joinedElsewhere) return null;
+
   if (!room || !rooms.includes(room.roomId)) {
     return (
       <JoinBeforeNavigate