feat: hide Run button, update LibreTECH branding, improve welcome lessons

- Hide Run button (live preview is stable)
- Update all references from librete.ch to LibreTECH
- Add context to repo links (Gitea Source, GitHub Mirror)
- Fix welcome lesson redundant text
- Slow down CRISPY animation to 8s
- Remove editor-tools margin-right

src/app.js

@@ -603,7 +603,7 @@ function runCode() {
 		elements.previewWrapper?.classList.add("matched");
 		setTimeout(() => {
 			elements.previewWrapper?.classList.remove("matched");
-		}, 5000);
+		}, 10000);
 
 		updateNavigationButtons();
 		updateProgressDisplay();