feat: add email signature template

Author: mateobelanger

assets/email_signature_template

@@ -0,0 +1,39 @@
+<table cellpadding="0" cellspacing="0" border="0" style="font-family: 'Arial', sans-serif; color: #e0e0e0; background: linear-gradient(135deg, #0a0a1a 0%, #1a1a3a 100%); padding: 10px; border-radius: 5px; border-left: 4px solid #00ccff; max-width: 500px;">
+  <tr>
+    <td style="vertical-align: top; padding-right: 15px; position: relative;">
+      <img src="https://pbs.twimg.com/profile_images/1867301329623748608/DZlijgnc_400x400.jpg" alt="Your Name" style="width: 80px; height: 80px; border-radius: 50%;">
+      <img src="https://avatars.githubusercontent.com/u/93353392?s=400&u=53d613dbc6b14bace9eedaaaf49de48eaefa69c7&v=4" alt="Playgrounds Logo" style="width: 30px; height: 30px; position: absolute; bottom: 0; right: 15px; border-radius: 4px;">
+    </td>
+    <td style="vertical-align: top;">
+      <table cellpadding="0" cellspacing="0" border="0">
+        <tr>
+          <td style="font-size: 18px; font-weight: bold; color: #ffffff;">Mathieu B.</td>
+        </tr>
+        <tr>
+          <td style="font-size: 13px; color: #00ccff; padding-bottom: 5px;">Engineer & PM</td>
+        </tr>
+        <tr>
+          <td style="font-size: 12px; color: #b0b0b0;">
+            <a href="mailto:mathieu@playgrounds.network" style="color: #b0b0b0; text-decoration: none;">mathieu@playgrounds.network</a>
+          </td>
+        </tr>
+        <tr>
+          <td style="padding-top: 10px;">
+            <a href="https://www.linkedin.com/in/mateobelanger/" target="_blank" style="text-decoration: none;">
+              <img src="https://cdn.jsdelivr.net/npm/simple-icons@v6/icons/linkedin.svg" alt="LinkedIn" style="width: 20px; height: 20px; margin-right: 5px; filter: brightness(0) invert(1);">
+            </a>
+            <a href="https://github.com/mateobelanger" target="_blank" style="text-decoration: none;">
+              <img src="https://cdn.jsdelivr.net/npm/simple-icons@v6/icons/github.svg" alt="GitHub" style="width: 20px; height: 20px; margin-right: 5px; filter: brightness(0) invert(1);">
+            </a>
+            <a href="https://x.com/belangermatteo" target="_blank" style="text-decoration: none;">
+              <img src="https://cdn.jsdelivr.net/npm/simple-icons@v6/icons/twitter.svg" alt="Twitter" style="width: 20px; height: 20px; filter: brightness(0) invert(1);">
+            </a>
+            <a href="https://t.me/belangermatteo" target="_blank" style="text-decoration: none;">
+              <img src="https://cdn.jsdelivr.net/npm/simple-icons@v6/icons/telegram.svg" alt="Telegram" style="width: 20px; height: 20px; filter: brightness(0) invert(1);">
+            </a>
+          </td>
+        </tr>
+      </table>
+    </td>
+  </tr>
+</table>