Update branding with DockMV logo and assets

- Replace text-based branding with logo icon in header
- Update README.md with full DockMV logo image
- Add favicon and logo-icon assets
- Add dockmv-icon to assets directory
- Update styles for logo display
- Rebuild web UI distribution

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

web/src/App.tsx

@@ -120,7 +120,7 @@ export default function App() {
   return (
     <div className="app">
       <header className="topbar">
-        <div className="brand"><span className="dot" />docker-migrate</div>
+        <div className="brand"><img src="/logo-icon.png" alt="" className="brand-logo" />DockMV</div>
         <nav className="tabs">
           <button className={`tab${view === 'containers' ? ' active' : ''}`} onClick={() => setView('containers')}>
             Containers