feat(connect): dedicated Claude.ai / ChatGPT browser connect picker

- Replace single 'Connect to Claude / ChatGPT' button with a modal picker
  offering Claude.ai web, Claude Desktop, Codex CLI, and ChatGPT/GPT Actions.
- Add /oauth/connect-claude-ai backend route that redirects to Anthropic's
  official https://claude.ai/api/mcp/auth_callback OAuth callback.
- Update MCP callback result page with browser-specific instructions for
  Claude.ai web, Claude Desktop, ChatGPT/GPT Actions, and Codex CLI.
- Deploy new app and hermes images to K8s.

product/app/index.html

@@ -94,7 +94,7 @@
       <section class="welcome">
         <h2>Connect your accounts</h2>
         <p>Connect once. Then ask Claude or ChatGPT to post, search your notes, or send email — without touching any of these apps.</p>
-        <button id="connect-mcp-btn" class="btn btn-primary" style="margin-top:16px;">Connect to Claude / ChatGPT</button>
+        <button id="connect-mcp-btn" class="btn btn-primary" style="margin-top:16px;" aria-label="Connect Claude.ai, ChatGPT, Claude Desktop, or Codex CLI" title="Connect Claude.ai, ChatGPT, Claude Desktop, or Codex CLI">Connect AI Client</button>
       </section>
 
       <section class="usage-bar" id="usage-bar">