fix(ui): open app deep links from chat after confirmation (#2932)

* fix(ui): open app deep links from chat after confirmation

DOMPurify's default URI policy stripped href from anchors with custom
application schemes (obsidian://, vscode://, ...), so every app link
rendered in chat was dead across web, desktop, VS Code, and mobile.

- Classify safe app-link schemes in lib/url.ts (browser-handled,
  scriptable, webview-internal, network, and self-deep-link schemes
  stay excluded) and let openExternalUrl accept them
- Keep app-link hrefs through the markdown sanitize hook
- Intercept app-link clicks in the markdown renderer and route them
  through a confirmation dialog (Trust and open / Open once, dismiss
  to cancel) mounted in the desktop/web app root and the mobile shell
- Persist per-device trusted schemes in a zustand store; trusted
  schemes open without asking again

* feat(settings): manage trusted app link schemes in General

Add an App links section to Settings > General listing the application
schemes trusted on this device with a delete action; removing a scheme
restores the confirmation dialog for it. Register the section in
settings search.

* fix(ui): enforce app link confirmation

* fix(ui): handle app links by runtime

* fix(vscode): keep app links unsupported

* fix(settings): clarify trusted app links

---------

Co-authored-by: Bohdan Triapitsyn <artmore@protonmail.com>

packages/ui/src/components/chat/AppLinkConfirmDialog.tsx

@@ -0,0 +1,77 @@
+import * as React from 'react';
+
+import { Button } from '@/components/ui/button';
+import {
+  Dialog,
+  DialogContent,
+  DialogDescription,
+  DialogFooter,
+  DialogHeader,
+  DialogTitle,
+} from '@/components/ui/dialog';
+import { useI18n } from '@/lib/i18n';
+import { getUrlScheme } from '@/lib/url';
+
+import {
+  getAppLinkConfirmationSnapshot,
+  settleAppLinkConfirmation,
+  subscribeAppLinkConfirmation,
+  type AppLinkConfirmationChoice,
+} from './appLinkConfirmation';
+
+/**
+ * App-level dialog confirming application deep links (obsidian://, vscode://,
+ * ...) rendered in chat markdown before the OS is asked to open them.
+ * Dismissing via the close button, Escape, or the backdrop cancels the open.
+ */
+export const AppLinkConfirmDialog = () => {
+  const { t } = useI18n();
+  const request = React.useSyncExternalStore(
+    subscribeAppLinkConfirmation,
+    getAppLinkConfirmationSnapshot,
+    getAppLinkConfirmationSnapshot,
+  );
+
+  const url = request?.url ?? '';
+  const scheme = getUrlScheme(url) ?? '';
+
+  const settle = React.useCallback((choice: AppLinkConfirmationChoice) => {
+    settleAppLinkConfirmation(choice);
+  }, []);
+
+  return (
+    <Dialog
+      open={Boolean(request)}
+      onOpenChange={(open: boolean) => {
+        if (!open) {
+          settle('cancel');
+        }
+      }}
+    >
+      <DialogContent>
+        <DialogHeader>
+          <DialogTitle>{t('chat.appLink.confirm.title')}</DialogTitle>
+          <DialogDescription>
+            {scheme
+              ? t('chat.appLink.confirm.description', { scheme: `${scheme}://` })
+              : t('chat.appLink.confirm.descriptionPlain')}
+          </DialogDescription>
+        </DialogHeader>
+        <div className="rounded-lg bg-[var(--surface-muted)] px-3 py-2 text-[13px] leading-relaxed break-all text-[var(--surface-foreground)]">
+          {url}
+        </div>
+        <DialogFooter>
+          <Button variant="ghost" autoFocus onClick={() => settle('cancel')}>
+            {t('chat.appLink.confirm.cancel')}
+          </Button>
+          <Button variant="outline" onClick={() => settle('trust')}>
+            {t('chat.appLink.confirm.trustAndOpen')}
+          </Button>
+          <Button variant="default" onClick={() => settle('open')}>
+            {t('chat.appLink.confirm.open')}
+          </Button>
+        </DialogFooter>
+      </DialogContent>
+    </Dialog>
+  );
+};