fix(brand/ux): real Biz Connect logo, branded loading screen, phone login, no blank gap

- Replace the leftover 'Your Virtual CXO' logo.png with the app icon (C mark) in every
  header (home/index/connect/dashboard) + the app icon on share.html; delete logo.png.
- Loading screen now shows the orbit mark + 'Biz Connect' wordmark + 'Loading…' (was bare).
- Keep the branded splash up until the chat list finishes loading — no blank/stuck gap
  after login (previously hidden before loadSidebar()).
- Login accepts email OR phone (field was type=email, which rejected phone numbers and so
  blocked the mobile-login that triggers the account merge). Label → 'Email or phone'.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

server/public/connect.html

@@ -76,7 +76,7 @@
 <script>if(new URLSearchParams(location.search).get('embed')==='1')document.documentElement.classList.add('embed');</script>
 <a href="/home" id="homeLink"><span data-ic="arrowLeft" data-sz="16"></span> Home</a>
 <div class="topbar" id="topbar">
-  <div class="brandrow"><img src="/logo.png" alt="" style="height:46px;width:auto;max-width:190px;border-radius:8px;object-fit:contain;background:#fff;padding:5px 12px;image-rendering:-webkit-optimize-contrast" onerror="this.replaceWith(Object.assign(document.createElement('div'),{className:'logo',textContent:'B'}))"><div class="brand">Biz <span>Connect</span></div></div>
+  <div class="brandrow"><img src="/icon-192.png" alt="" style="height:46px;width:auto;max-width:190px;border-radius:8px;object-fit:contain;background:#fff;padding:5px 12px;image-rendering:-webkit-optimize-contrast" onerror="this.replaceWith(Object.assign(document.createElement('div'),{className:'logo',textContent:'B'}))"><div class="brand">Biz <span>Connect</span></div></div>
   <div class="agentchip" id="agentChip"></div>
 </div>
 <div class="topbar2" id="bar"><span id="barStatus"></span><button id="endBtn">End session</button></div>