Refactor project structure and update configurations. Now first working version

- Updated `.air.conf` for Nix compatibility and simplified build commands.
- Enhanced `.gitignore` to include `tmp` directory.
- Improved `README.md` with clearer instructions and added language details.
- Refined CSS styles for better UI consistency and added alert styles.
- Upgraded `flake.nix` to use Go 1.24 and improved shell environment setup.
- Modified authentication logic in `auth.go` for better user handling.
- Updated `main.go` to dynamically set the listening port and improved logging.
- Added new `routes.go` file for handling game entry and history.
- Enhanced user models and added statistics tracking in `models.go`.
- Improved template rendering and added user feedback messages in HTML templates.
- Removed obsolete build error logs and binaries.

.air.conf

@@ -1,17 +1,14 @@
 root = "."
-tmp_dir = "tmp"
 
 [build]
-  cmd = "go build -o ./tmp/main ./src/main.go"
-  bin = "tmp/main"
-  full_bin = "tmp/main"
-  include_ext = ["go", "tpl", "tmpl", "html", "css", "js"]
-  exclude_dir = ["tmp", "vendor"]
+  cmd = "nix develop -c  go build -o ./tmp/main ./src/..." # for nix users
+  include_ext = ["go", "html", "css"]
+  exclude_dir = ["tmp"]
 
 [log]
+  level = "warn"
   time = true
 
-[colors]
-  main = "yellow"
-  watcher = "cyan"
-  build = "green"
+[env]
+  GIN_MODE = "debug" # change to "release" for production
+  APP_PORT = 18765