added a flag to hide settings (#5263)

Added an optional flag in settings.yml to hide the settings button in no
login servers. When hidden, users can no longer:

- Open the Settings modal at all (gear button is hidden)
- Change General preferences (tool picker mode, hide unavailable
tools/conversions, auto‑unzip and file limit)
- Configure keyboard shortcuts (Hotkeys / Keyboard Shortcuts section)
- Use the in‑app update checker UI (see current/latest version, check
for updates, view update details)
- Note: When enableLogin === true, the flag is ignored and the Settings
button remains visible.

---------

Co-authored-by: Anthony Stirling <[email protected]>
Co-authored-by: Reece Browne <[email protected]>

app/core/src/main/java/stirling/software/SPDF/controller/api/misc/ConfigController.java

@@ -84,6 +84,9 @@ public class ConfigController {
             boolean enableLogin =
                     applicationProperties.getSecurity().isEnableLogin() && userService != null;
             configData.put("enableLogin", enableLogin);
+            configData.put(
+                    "showSettingsWhenNoLogin",
+                    applicationProperties.getSystem().isShowSettingsWhenNoLogin());
 
             // Mail settings - check both SMTP enabled AND invites enabled
             boolean smtpEnabled = applicationProperties.getMail().isEnabled();