Add Go to Line command to the text editor

Objo Studio should provide a Go to Line command for the code editor so users can jump directly to a specific line in the active method or event body. This would make it quicker to navigate larger methods, follow diagnostics, or move to a line number referenced in discussion, screenshots, or support messages.

The command should be available from the Edit menu and through a keyboard shortcut. On macOS, the requested shortcut is Xcode-style Cmd+L for "Jump to Line". On Windows and Linux, Ctrl+G would be the conventional equivalent.