Refactor Telegram bot and web application for improved functionality

- Disabled the default menu button in the Telegram bot, allowing users to access the app via a direct link.
- Updated the initData validation process to ensure URL-decoded values are used in the data-check string.
- Enhanced error handling in the web application to provide more informative access denial messages.
- Removed unnecessary debug information from the access denied section in the web app.
- Cleaned up the web application code by removing unused functions and improving CSS styles for hidden elements.

webapp/style.css

@@ -36,6 +36,11 @@ body {
   margin-bottom: 12px;
 }
 
+.header[hidden],
+.weekdays[hidden] {
+  display: none !important;
+}
+
 .nav {
   width: 40px;
   height: 40px;
@@ -166,12 +171,6 @@ body {
   font-weight: 600;
 }
 
-.access-denied .debug {
-  font-size: 0.75rem;
-  margin-top: 12px;
-  word-break: break-all;
-}
-
 .access-denied[hidden] {
   display: none !important;
 }