Add app version display to login page and profile About card

Version is set via APP_VERSION in .env, defaulting to 1.0.0.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app/templates/auth/login.html

@@ -29,5 +29,6 @@
       </form>
     </div>
   </div>
+  <p style="text-align:center; color:var(--text-muted); font-size:0.75rem; margin-top:1.5rem; opacity:0.6;">v{{ app_version }}</p>
 </body>
 </html>

app/templates/profile/profile.html

@@ -76,6 +76,14 @@
   {% include "partials/crop_modal.html" %}
   </div>
 
+  <div class="card" style="margin-top:1.5rem;">
+    <h2 style="font-size:0.95rem; color:var(--text-muted); margin-bottom:0.75rem;">About</h2>
+    <div style="display:flex; justify-content:space-between; align-items:center;">
+      <span style="font-weight:500;">Skins &amp; Pins</span>
+      <span style="color:var(--text-muted); font-size:0.85rem; font-family:monospace;">v{{ app_version }}</span>
+    </div>
+  </div>
+
   <div style="margin-top: 1.5rem;">
     <a href="/logout" class="btn btn-ghost">Log out</a>
   </div>