Update Gemfile.lock to remove unused dependencies and add webrick; add footer to index.erb with copyright information

Gemfile.lock

@@ -6,7 +6,6 @@ GEM
     logger (1.7.0)
     multi_json (1.21.1)
     mustermann (3.1.1)
-    nio4r (2.7.5)
     nokogiri (1.19.3-aarch64-linux-gnu)
       racc (~> 1.4)
     nokogiri (1.19.3-aarch64-linux-musl)
@@ -23,8 +22,6 @@ GEM
       racc (~> 1.4)
     nokogiri (1.19.3-x86_64-linux-musl)
       racc (~> 1.4)
-    puma (8.0.1)
-      nio4r (~> 2.0)
     racc (1.8.1)
     rack (3.2.6)
     rack-protection (4.2.1)
@@ -60,6 +57,7 @@ GEM
       sinatra (= 4.2.1)
       tilt (~> 2.0)
     tilt (2.7.0)
+    webrick (1.9.2)
 
 PLATFORMS
   aarch64-linux-gnu
@@ -72,12 +70,12 @@ PLATFORMS
   x86_64-linux-musl
 
 DEPENDENCIES
-  puma
   rackup
   roo
   rubyXL
   sinatra
   sinatra-contrib
+  webrick
 
 BUNDLED WITH
    2.5.3

views/index.erb

@@ -459,4 +459,6 @@
 </script>
 
 </body>
+<footer style="margin-top: 3rem; font-size: 0.8rem; color: #555; text-align: center;">
+  &copy; Визуализация работы сетей Хопфилда и Хэмминга by Антипенко Д.А. - 2026. Ruby/Sinatra
 </html>