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/plugins/react-custom-html-parser.tsx

@@ -23,6 +23,7 @@ import Linkify from 'linkify-react';
 import { ErrorBoundary } from 'react-error-boundary';
 import { ChildNode } from 'domhandler';
 import { stripTrackingParams } from '../utils/urlTracking';
+import { lotusPermalinkToMatrixTo } from './lotus-permalink';
 import * as css from '../styles/CustomHtml.css';
 import {
   getMxIdLocalPart,
@@ -118,6 +119,22 @@ export const setStripTrackingOnRender = (enabled: boolean): void => {
 const cleanHref = (href: string): string =>
   stripTrackingOnRender ? stripTrackingParams(href) : href;
 
+// [Gitea #130] Links to THIS deployment's room routes render and click like
+// matrix.to links. The base is set once from the client config
+// (ClientNonUIFeatures) because this module has no access to hooks.
+let lotusPermalinkBase: string | undefined;
+export const setLotusPermalinkBase = (baseUrl: string | undefined): void => {
+  lotusPermalinkBase = baseUrl;
+};
+/**
+ * The matrix.to form of `href` when it is a matrix.to link or a Lotus
+ * permalink; undefined for every other link.
+ */
+export const toMatrixToHref = (href: string): string | undefined => {
+  if (testMatrixTo(href)) return href;
+  return lotusPermalinkBase ? lotusPermalinkToMatrixTo(lotusPermalinkBase, href) : undefined;
+};
+
 export const LINKIFY_OPTS: LinkifyOpts = {
   attributes: {
     target: '_blank',
@@ -235,8 +252,10 @@ export const factoryRenderLinkifyWithMention = (
     attributes,
     content,
   }) => {
-    if (tagName === 'a' && testMatrixTo(tryDecodeURIComponent(attributes.href))) {
-      const mention = mentionRender(tryDecodeURIComponent(attributes.href));
+    const matrixHref =
+      tagName === 'a' ? toMatrixToHref(tryDecodeURIComponent(attributes.href)) : undefined;
+    if (matrixHref) {
+      const mention = mentionRender(matrixHref);
       if (mention) return mention;
     }
 
@@ -559,7 +578,9 @@ export const getReactCustomHtmlParser = (
           }
         }
 
-        if (name === 'a' && testMatrixTo(tryDecodeURIComponent(String(props.href)))) {
+        const matrixHref =
+          name === 'a' ? toMatrixToHref(tryDecodeURIComponent(String(props.href))) : undefined;
+        if (matrixHref) {
           const content = children.find((child) => !(child instanceof DOMText))
             ? undefined
             : children.map((c) => (c instanceof DOMText ? c.data : '')).join();
@@ -567,7 +588,7 @@ export const getReactCustomHtmlParser = (
           const mention = renderMatrixMention(
             mx,
             roomId,
-            tryDecodeURIComponent(String(props.href)),
+            matrixHref,
             makeMentionCustomProps(params.handleMentionClick, content),
           );