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/ClientNonUIFeatures.tsx

@@ -20,11 +20,15 @@ import { notificationPermission, setFavicon, showOsNotification } from '../../ut
 import { NOTIFICATION_SOUND_MAP } from '../../utils/notificationSounds';
 import { useSetting } from '../../state/hooks/settings';
 import { settingsAtom } from '../../state/settings';
-import { setStripTrackingOnRender } from '../../plugins/react-custom-html-parser';
+import {
+  setLotusPermalinkBase,
+  setStripTrackingOnRender,
+} from '../../plugins/react-custom-html-parser';
 import { useSettingsSync } from '../../hooks/useSettingsSync';
 import { usePwaInstallPrompt } from '../../hooks/usePwaInstallPrompt';
 import { allInvitesAtom } from '../../state/room-list/inviteList';
 import { useMatrixClient } from '../../hooks/useMatrixClient';
+import { useClientConfig } from '../../hooks/useClientConfig';
 import { useHydrateMsgDrafts } from '../../hooks/useHydrateMsgDrafts';
 import { useSearchCacheInvalidation } from '../../utils/searchCacheInvalidation';
 import {
@@ -92,6 +96,15 @@ function SystemEmojiFeature() {
 }
 
 // [Gitea #103] Mirror the privacy toggle into the html parser's module flag.
+function LotusPermalinkFeature() {
+  const { hashRouter } = useClientConfig();
+  useEffect(() => {
+    setLotusPermalinkBase(getOriginBaseUrl(hashRouter));
+    return () => setLotusPermalinkBase(undefined);
+  }, [hashRouter]);
+  return null;
+}
+
 function TrackingParamsFeature() {
   const [stripTracking] = useSetting(settingsAtom, 'stripTrackingParams');
   useEffect(() => {
@@ -928,6 +941,7 @@ export function ClientNonUIFeatures({ children }: ClientNonUIFeaturesProps) {
       <SearchCacheInvalidationFeature />
       <SystemEmojiFeature />
       <PageZoomFeature />
+      <LotusPermalinkFeature />
       <TrackingParamsFeature />
       <SettingsSyncFeature />
       <PwaInstallFeature />