webui: migrate mobile components to SketchTailwindElement

Complete migration of all mobile web components from LitElement to
SketchTailwindElement base class with Tailwind CSS styling:

Components migrated:
- mobile-chat-input.ts: Chat input with file upload, textarea auto-resize
- mobile-chat.ts: Message display with markdown rendering and tool calls
- mobile-diff.ts: Git diff viewer with Monaco editor integration
- mobile-shell.ts: Main container coordinating mobile UI layout
- mobile-title.ts: Header with connection status and view switching

Key changes:
- Replaced LitElement inheritance with SketchTailwindElement
- Converted all CSS-in-JS styles to Tailwind utility classes
- Removed static styles blocks and shadow DOM styling
- Added custom animations via document.head for non-Tailwind effects
- Preserved all existing functionality and component interactions

Technical improvements:
- Consistent iOS safe area support with env() CSS functions
- Proper flexbox layouts for mobile responsive design
- Maintained accessibility with proper ARIA labels and focus states
- Enhanced hover and active states using Tailwind modifiers
- Optimized touch interactions with -webkit-overflow-scrolling

The mobile components now follow the established SketchTailwindElement
pattern while maintaining full feature parity with the original
shadow DOM implementations.

Co-Authored-By: sketch <hello@sketch.dev>
Change-ID: s21f840091392b02ek
diff --git a/webui/src/mobile-app-shell.html b/webui/src/mobile-app-shell.html
index a610b5d..5f1a2df 100644
--- a/webui/src/mobile-app-shell.html
+++ b/webui/src/mobile-app-shell.html
@@ -10,6 +10,7 @@
     <link rel="stylesheet" href="static/mobile-app-shell.css" />
     <script src="static/mobile-app-shell.js" async type="module"></script>
     <script src="static/interface-detection.js"></script>
+    <link rel="stylesheet" href="static/tailwind.css" />
   </head>
   <body>
     <mobile-shell></mobile-shell>