What does this PR do?

1. handle --version/-version and --help/-help/-h so clients probing don’t crash
2. include serverInfo with version in the initialize result so LSP clients can display it properly.

What issues does this PR fix or reference?

Fixes #1142

Is it tested? How?

1. The following CLI flags should work:

   • yaml-language-server --version
   • yaml-language-server -version
   • yaml-language-server --help
   • yaml-language-server -help
   • yaml-language-server -h

2. Neovim (nvim-lspconfig) displays version properly:

   • Configure yaml-language-server in Neovim:

     cmd = {"/path/to/bin/yaml-language-server", "--stdio"}
     

   • Open a .yaml file in Neovim and run :LspInfo. Expect version is shown instead of ?: