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/lib/settings/search.ts

@@ -50,7 +50,6 @@ const SETTINGS_SEARCH_ITEMS: readonly SettingsSearchItem[] = [
     page: 'appearance',
     titleKey: 'settings.openchamber.visual.field.weekStartsOn',
     keywords: ['calendar', 'monday', 'sunday'],
-    isAvailable: (ctx) => !ctx.isVSCode,
   },
   {
     id: 'appearance.light-theme',
@@ -177,6 +176,13 @@ const SETTINGS_SEARCH_ITEMS: readonly SettingsSearchItem[] = [
     descriptionKey: 'settings.openchamber.visual.field.sendAnonymousUsageReportsHint',
     keywords: ['telemetry', 'analytics'],
   },
+  {
+    id: 'general.app-links',
+    page: 'general',
+    titleKey: 'settings.openchamber.appLinks.title',
+    descriptionKey: 'settings.openchamber.appLinks.info',
+    keywords: ['security', 'app link', 'deep link', 'scheme', 'protocol', 'obsidian', 'notion'],
+  },
   {
     id: 'chat.render-mode',
     page: 'chat',