LSP File Lifecycle Management

What: Four new methods for synchronizing file state with Language Server Protocol servers

Details:

• getAllServers() - Returns Map of all initialized LSP servers for monitoring
• openFile(path, content) - Sends textDocument/didOpen with proper languageId mapping
• changeFile(path, content) - Sends textDocument/didChange, falls back to openFile if server not running
• closeFile(path) - Sends textDocument/didClose for cleanup
• Configuration changed from fileExtensions array to extensionToLanguage object for proper language ID support
• Evidence: ym2() at line 446307, methods at lines 446405-446454