T-3bd620d

Pre-release built from commit 3bd620d.

This is a pre-release version for testing purposes; it may be somewhat unstable and has not been fully tested.

Added

• Import projects - .cbp files can now be imported from the "Open Project" dialog. Invalid or duplicate names are coerced rather than rejected (for example a<b>c:d becomes a_b_c_d), and duplicates receive a _2 / _3 suffix instead of overwriting an existing project.
• First-run language selection - first-time visitors are asked to choose a language before they start. The dialog cannot be dismissed without a selection, and a hint afterwards points to the Language button.
• Spotlight toolbar tour - on first entry into the editor, a guided tour highlights each toolbar control in place with a step-by-step tooltip. It can be replayed at any time with the ? button in the toolbar or F1, and skipped with the Skip button or Esc.
• CMD launcher - Launch.ps1 is replaced by Launch.cmd. The server now runs in the foreground of the launcher window, so closing the window or pressing Ctrl+C terminates it along with all of its child processes; no orphaned processes remain. The port can be overridden with CUBLOCKY_URL=http://localhost:6000 Launch.cmd.

Fixed

• Import requests with an empty body, a missing mod field, or a blank name are now rejected with a 400 response instead of silently creating a project named "My Mod" from the model default.
• Duplicate browser tabs on startup: launchBrowser is now disabled in launchSettings.json and the browser-opener lines were removed from the launcher. The server opens exactly one tab, once it is actually listening.
• Guide and onboarding copy was rewritten to use more consistent, neutral wording across all three languages.