Ottimizzazione UI player, rotazione head tilt invertita, prefisso playlist in Home e implementazione Identity QR modal e interceptor API

src/app/services/settings.service.ts

@@ -53,6 +53,9 @@ export class SettingsService {
   /** Avanzamento a pagine del karaoke manuale: true = i tasti next/prev voltano la pagina */
   public karaokePageScrollMode = signal<boolean>(false);
 
+  /** Identificativo utente univoco per la gestione delle comunità */
+  public userUuid = signal<string>('');
+
   private wakeLock: any = null;
 
   // PWA installation signals
@@ -63,6 +66,22 @@ export class SettingsService {
   public isAndroid = signal<boolean>(false);
 
   constructor() {
+    // Gestione/Generazione ID utente univoco
+    let savedUuid = localStorage.getItem('user-uuid');
+    if (!savedUuid) {
+      if (typeof crypto !== 'undefined' && crypto.randomUUID) {
+        savedUuid = crypto.randomUUID();
+      } else {
+        savedUuid = 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace(/[xy]/g, (c) => {
+          const r = Math.random() * 16 | 0;
+          const v = c === 'x' ? r : (r & 0x3 | 0x8);
+          return v.toString(16);
+        });
+      }
+      localStorage.setItem('user-uuid', savedUuid);
+    }
+    this.userUuid.set(savedUuid);
+
     // Detect PWA status
     try {
       this.isStandalone.set(
@@ -117,6 +136,7 @@ export class SettingsService {
       localStorage.setItem(migrationKey, 'true');
     }
 
+
     const savedChords = localStorage.getItem('show-chords-default');
     if (savedChords !== null) {
       this.showChordsDefault.set(savedChords === 'true');
@@ -397,6 +417,14 @@ export class SettingsService {
     this.chordNotationPreference.set(val);
   }
 
+  setUserUuid(uuid: string) {
+    const trimmed = uuid.trim();
+    if (trimmed) {
+      this.userUuid.set(trimmed);
+      localStorage.setItem('user-uuid', trimmed);
+    }
+  }
+
   async installPwa() {
     const promptEvent = this.deferredPrompt();
     if (!promptEvent) {