move theme toggle to fixed bottom-right corner

Repositions the dark/light mode button from the header to a fixed
position in the bottom-right corner (always visible). Bumps size
to 44px for WCAG touch target compliance. Also makes login text
and icon white in dark mode.

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

groups/home/bootstrap5/home1.html

@@ -76,14 +76,6 @@
               <div id="login-text">Login</div>
               <div id="login-icon"><i class="fas fa-user" aria-hidden="true"></i></div>
             </a>
-            <button
-              id="theme-toggle"
-              @click="toggleTheme"
-              :aria-label="isDark ? 'Switch to light mode' : 'Switch to dark mode'"
-              type="button"
-            >
-              <i :class="isDark ? 'fas fa-sun' : 'fas fa-moon'" aria-hidden="true"></i>
-            </button>
             <img
               id="library-logo"
               class="image-fail"
@@ -102,6 +94,14 @@
           <!-- end of col-xs-12 -->
         </div>
         <!--end of row-->
+        <button
+          id="theme-toggle"
+          @click="toggleTheme"
+          :aria-label="isDark ? 'Switch to light mode' : 'Switch to dark mode'"
+          type="button"
+        >
+          <i :class="isDark ? 'fas fa-sun' : 'fas fa-moon'" aria-hidden="true"></i>
+        </button>
       </div>
       <!--end of Vue app1-->
     </div>