feat(radio): add tooltips + aria-labels on every player button

Radio audio-player buttons (skip-prev, play/pause FAB, skip-next, mute,
volume slider) had zero matTooltip or aria-label. The UX audit flagged
this: "Skip-prev / Skip-next — what do they skip? In radio, is the
next 'track' the next station? Next in favourites? Random? Without a
tooltip the buttons trade silently." Same critique applied to mute
and play/pause for screen-reader users.

Add hover tooltips and screen-reader labels on all 5 controls. Skip
prev/next say "Previous station" / "Next station" so the behaviour is
explicit (they walk the active filtered list). Play/Pause flips its
label with state. Mute/unmute flips when isMuted() || volume === 0.
Volume slider gets its own label so the slider thumb is announced
correctly.

i18n: 7 new AUDIO_PLAYER.* keys translated across all 17 non-English
locales by per-locale agents; all 18 locales pass coverage and
placeholder integrity checks.

52/52 ui-playback tests still pass.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

apps/web/src/assets/i18n/ar.json

@@ -379,6 +379,15 @@
         "LIGHT_THEME": "فاتح",
         "SYSTEM_THEME": "النظام"
     },
+    "AUDIO_PLAYER": {
+        "PLAY": "تشغيل",
+        "PAUSE": "إيقاف مؤقت",
+        "PREVIOUS_STATION": "المحطة السابقة",
+        "NEXT_STATION": "المحطة التالية",
+        "MUTE": "كتم الصوت",
+        "UNMUTE": "إلغاء كتم الصوت",
+        "VOLUME": "مستوى الصوت"
+    },
     "PLAYBACK_DIAGNOSTICS": {
         "UNSUPPORTED_CONTAINER": {
             "TITLE": "This stream container is likely unsupported by the browser player",

apps/web/src/assets/i18n/ary.json

@@ -379,6 +379,15 @@
         "LIGHT_THEME": "فاتح",
         "SYSTEM_THEME": "النظام"
     },
+    "AUDIO_PLAYER": {
+        "PLAY": "شغل",
+        "PAUSE": "وقّف",
+        "PREVIOUS_STATION": "المحطة السابقة",
+        "NEXT_STATION": "المحطة التالية",
+        "MUTE": "كتم الصوت",
+        "UNMUTE": "رجّع الصوت",
+        "VOLUME": "الصوت"
+    },
     "PLAYBACK_DIAGNOSTICS": {
         "UNSUPPORTED_CONTAINER": {
             "TITLE": "This stream container is likely unsupported by the browser player",

apps/web/src/assets/i18n/by.json

@@ -379,6 +379,15 @@
         "LIGHT_THEME": "Светлая",
         "SYSTEM_THEME": "Сістэмная"
     },
+    "AUDIO_PLAYER": {
+        "PLAY": "Прайграць",
+        "PAUSE": "Паўза",
+        "PREVIOUS_STATION": "Папярэдняя станцыя",
+        "NEXT_STATION": "Наступная станцыя",
+        "MUTE": "Адключыць гук",
+        "UNMUTE": "Уключыць гук",
+        "VOLUME": "Гучнасць"
+    },
     "PLAYBACK_DIAGNOSTICS": {
         "UNSUPPORTED_CONTAINER": {
             "TITLE": "This stream container is likely unsupported by the browser player",

apps/web/src/assets/i18n/de.json

@@ -379,6 +379,15 @@
         "LIGHT_THEME": "Hell",
         "SYSTEM_THEME": "System"
     },
+    "AUDIO_PLAYER": {
+        "PLAY": "Wiedergabe",
+        "PAUSE": "Pause",
+        "PREVIOUS_STATION": "Vorheriger Sender",
+        "NEXT_STATION": "Nächster Sender",
+        "MUTE": "Stummschalten",
+        "UNMUTE": "Stummschaltung aufheben",
+        "VOLUME": "Lautstärke"
+    },
     "PLAYBACK_DIAGNOSTICS": {
         "UNSUPPORTED_CONTAINER": {
             "TITLE": "This stream container is likely unsupported by the browser player",

apps/web/src/assets/i18n/el.json

@@ -379,6 +379,15 @@
         "LIGHT_THEME": "Ανοιχτό",
         "SYSTEM_THEME": "Σύστημα"
     },
+    "AUDIO_PLAYER": {
+        "PLAY": "Αναπαραγωγή",
+        "PAUSE": "Παύση",
+        "PREVIOUS_STATION": "Προηγούμενος σταθμός",
+        "NEXT_STATION": "Επόμενος σταθμός",
+        "MUTE": "Σίγαση",
+        "UNMUTE": "Κατάργηση σίγασης",
+        "VOLUME": "Ένταση"
+    },
     "PLAYBACK_DIAGNOSTICS": {
         "UNSUPPORTED_CONTAINER": {
             "TITLE": "This stream container is likely unsupported by the browser player",

apps/web/src/assets/i18n/en.json

@@ -379,6 +379,15 @@
         "LIGHT_THEME": "Light",
         "SYSTEM_THEME": "System"
     },
+    "AUDIO_PLAYER": {
+        "PLAY": "Play",
+        "PAUSE": "Pause",
+        "PREVIOUS_STATION": "Previous station",
+        "NEXT_STATION": "Next station",
+        "MUTE": "Mute",
+        "UNMUTE": "Unmute",
+        "VOLUME": "Volume"
+    },
     "PLAYBACK_DIAGNOSTICS": {
         "UNSUPPORTED_CONTAINER": {
             "TITLE": "This stream container is likely unsupported by the browser player",

apps/web/src/assets/i18n/es.json

@@ -379,6 +379,15 @@
         "LIGHT_THEME": "Claro",
         "SYSTEM_THEME": "Sistema"
     },
+    "AUDIO_PLAYER": {
+        "PLAY": "Reproducir",
+        "PAUSE": "Pausar",
+        "PREVIOUS_STATION": "Emisora anterior",
+        "NEXT_STATION": "Emisora siguiente",
+        "MUTE": "Silenciar",
+        "UNMUTE": "Activar sonido",
+        "VOLUME": "Volumen"
+    },
     "PLAYBACK_DIAGNOSTICS": {
         "UNSUPPORTED_CONTAINER": {
             "TITLE": "This stream container is likely unsupported by the browser player",

apps/web/src/assets/i18n/fr.json

@@ -379,6 +379,15 @@
         "LIGHT_THEME": "Clair",
         "SYSTEM_THEME": "Système"
     },
+    "AUDIO_PLAYER": {
+        "PLAY": "Lecture",
+        "PAUSE": "Pause",
+        "PREVIOUS_STATION": "Station précédente",
+        "NEXT_STATION": "Station suivante",
+        "MUTE": "Muet",
+        "UNMUTE": "Activer le son",
+        "VOLUME": "Volume"
+    },
     "PLAYBACK_DIAGNOSTICS": {
         "UNSUPPORTED_CONTAINER": {
             "TITLE": "This stream container is likely unsupported by the browser player",

apps/web/src/assets/i18n/it.json

@@ -379,6 +379,15 @@
         "LIGHT_THEME": "Chiaro",
         "SYSTEM_THEME": "Sistema"
     },
+    "AUDIO_PLAYER": {
+        "PLAY": "Riproduci",
+        "PAUSE": "Pausa",
+        "PREVIOUS_STATION": "Stazione precedente",
+        "NEXT_STATION": "Stazione successiva",
+        "MUTE": "Disattiva audio",
+        "UNMUTE": "Attiva audio",
+        "VOLUME": "Volume"
+    },
     "PLAYBACK_DIAGNOSTICS": {
         "UNSUPPORTED_CONTAINER": {
             "TITLE": "This stream container is likely unsupported by the browser player",

apps/web/src/assets/i18n/ja.json

@@ -379,6 +379,15 @@
         "LIGHT_THEME": "ライト",
         "SYSTEM_THEME": "システム"
     },
+    "AUDIO_PLAYER": {
+        "PLAY": "再生",
+        "PAUSE": "一時停止",
+        "PREVIOUS_STATION": "前の局",
+        "NEXT_STATION": "次の局",
+        "MUTE": "ミュート",
+        "UNMUTE": "ミュート解除",
+        "VOLUME": "音量"
+    },
     "PLAYBACK_DIAGNOSTICS": {
         "UNSUPPORTED_CONTAINER": {
             "TITLE": "This stream container is likely unsupported by the browser player",

apps/web/src/assets/i18n/ko.json

@@ -379,6 +379,15 @@
         "LIGHT_THEME": "밝게",
         "SYSTEM_THEME": "시스템"
     },
+    "AUDIO_PLAYER": {
+        "PLAY": "재생",
+        "PAUSE": "일시정지",
+        "PREVIOUS_STATION": "이전 방송국",
+        "NEXT_STATION": "다음 방송국",
+        "MUTE": "음소거",
+        "UNMUTE": "음소거 해제",
+        "VOLUME": "볼륨"
+    },
     "PLAYBACK_DIAGNOSTICS": {
         "UNSUPPORTED_CONTAINER": {
             "TITLE": "This stream container is likely unsupported by the browser player",

apps/web/src/assets/i18n/nl.json

@@ -379,6 +379,15 @@
         "LIGHT_THEME": "Licht",
         "SYSTEM_THEME": "Systeem"
     },
+    "AUDIO_PLAYER": {
+        "PLAY": "Afspelen",
+        "PAUSE": "Pauzeren",
+        "PREVIOUS_STATION": "Vorige zender",
+        "NEXT_STATION": "Volgende zender",
+        "MUTE": "Dempen",
+        "UNMUTE": "Dempen opheffen",
+        "VOLUME": "Volume"
+    },
     "PLAYBACK_DIAGNOSTICS": {
         "UNSUPPORTED_CONTAINER": {
             "TITLE": "This stream container is likely unsupported by the browser player",

apps/web/src/assets/i18n/pl.json

@@ -379,6 +379,15 @@
         "LIGHT_THEME": "Jasny",
         "SYSTEM_THEME": "Systemowy"
     },
+    "AUDIO_PLAYER": {
+        "PLAY": "Odtwórz",
+        "PAUSE": "Wstrzymaj",
+        "PREVIOUS_STATION": "Poprzednia stacja",
+        "NEXT_STATION": "Następna stacja",
+        "MUTE": "Wycisz",
+        "UNMUTE": "Wyłącz wyciszenie",
+        "VOLUME": "Głośność"
+    },
     "PLAYBACK_DIAGNOSTICS": {
         "UNSUPPORTED_CONTAINER": {
             "TITLE": "This stream container is likely unsupported by the browser player",

apps/web/src/assets/i18n/pt.json

@@ -379,6 +379,15 @@
         "LIGHT_THEME": "Claro",
         "SYSTEM_THEME": "Sistema"
     },
+    "AUDIO_PLAYER": {
+        "PLAY": "Reproduzir",
+        "PAUSE": "Pausar",
+        "PREVIOUS_STATION": "Estação anterior",
+        "NEXT_STATION": "Próxima estação",
+        "MUTE": "Silenciar",
+        "UNMUTE": "Ativar som",
+        "VOLUME": "Volume"
+    },
     "PLAYBACK_DIAGNOSTICS": {
         "UNSUPPORTED_CONTAINER": {
             "TITLE": "This stream container is likely unsupported by the browser player",

apps/web/src/assets/i18n/ru.json

@@ -379,6 +379,15 @@
         "LIGHT_THEME": "Светлая",
         "SYSTEM_THEME": "Системная"
     },
+    "AUDIO_PLAYER": {
+        "PLAY": "Воспроизвести",
+        "PAUSE": "Пауза",
+        "PREVIOUS_STATION": "Предыдущая станция",
+        "NEXT_STATION": "Следующая станция",
+        "MUTE": "Отключить звук",
+        "UNMUTE": "Включить звук",
+        "VOLUME": "Громкость"
+    },
     "PLAYBACK_DIAGNOSTICS": {
         "UNSUPPORTED_CONTAINER": {
             "TITLE": "Контейнер потока, вероятно, не поддерживается встроенным браузерным плеером",

apps/web/src/assets/i18n/tr.json

@@ -379,6 +379,15 @@
         "LIGHT_THEME": "Açık",
         "SYSTEM_THEME": "Sistem"
     },
+    "AUDIO_PLAYER": {
+        "PLAY": "Oynat",
+        "PAUSE": "Duraklat",
+        "PREVIOUS_STATION": "Önceki istasyon",
+        "NEXT_STATION": "Sonraki istasyon",
+        "MUTE": "Sesi kapat",
+        "UNMUTE": "Sesi aç",
+        "VOLUME": "Ses seviyesi"
+    },
     "PLAYBACK_DIAGNOSTICS": {
         "UNSUPPORTED_CONTAINER": {
             "TITLE": "This stream container is likely unsupported by the browser player",

apps/web/src/assets/i18n/zh.json

@@ -379,6 +379,15 @@
         "LIGHT_THEME": "浅色",
         "SYSTEM_THEME": "跟随系统"
     },
+    "AUDIO_PLAYER": {
+        "PLAY": "播放",
+        "PAUSE": "暂停",
+        "PREVIOUS_STATION": "上一个电台",
+        "NEXT_STATION": "下一个电台",
+        "MUTE": "静音",
+        "UNMUTE": "取消静音",
+        "VOLUME": "音量"
+    },
     "PLAYBACK_DIAGNOSTICS": {
         "UNSUPPORTED_CONTAINER": {
             "TITLE": "This stream container is likely unsupported by the browser player",

apps/web/src/assets/i18n/zhtw.json

@@ -379,6 +379,15 @@
         "LIGHT_THEME": "淺色",
         "SYSTEM_THEME": "跟隨系統"
     },
+    "AUDIO_PLAYER": {
+        "PLAY": "播放",
+        "PAUSE": "暫停",
+        "PREVIOUS_STATION": "上一個電台",
+        "NEXT_STATION": "下一個電台",
+        "MUTE": "靜音",
+        "UNMUTE": "取消靜音",
+        "VOLUME": "音量"
+    },
     "PLAYBACK_DIAGNOSTICS": {
         "UNSUPPORTED_CONTAINER": {
             "TITLE": "This stream container is likely unsupported by the browser player",

libs/ui/playback/src/lib/audio-player/audio-player.component.ts

@@ -16,7 +16,9 @@ import { FormsModule } from '@angular/forms';
 import { MatButtonModule } from '@angular/material/button';
 import { MatIconModule } from '@angular/material/icon';
 import { MatSliderModule } from '@angular/material/slider';
+import { MatTooltip } from '@angular/material/tooltip';
 import { Store } from '@ngrx/store';
+import { TranslatePipe } from '@ngx-translate/core';
 import { ChannelActions } from '@iptvnator/m3u-state';
 
 @Component({
@@ -67,6 +69,12 @@ import { ChannelActions } from '@iptvnator/m3u-state';
                     <button
                         mat-icon-button
                         class="skip-btn"
+                        [matTooltip]="
+                            'AUDIO_PLAYER.PREVIOUS_STATION' | translate
+                        "
+                        [attr.aria-label]="
+                            'AUDIO_PLAYER.PREVIOUS_STATION' | translate
+                        "
                         (click)="switchChannel('previous')"
                     >
                         <mat-icon>skip_previous</mat-icon>
@@ -75,6 +83,18 @@ import { ChannelActions } from '@iptvnator/m3u-state';
                     <button
                         class="play-btn"
                         mat-fab
+                        [matTooltip]="
+                            (playState() === 'play'
+                                ? 'AUDIO_PLAYER.PAUSE'
+                                : 'AUDIO_PLAYER.PLAY'
+                            ) | translate
+                        "
+                        [attr.aria-label]="
+                            (playState() === 'play'
+                                ? 'AUDIO_PLAYER.PAUSE'
+                                : 'AUDIO_PLAYER.PLAY'
+                            ) | translate
+                        "
                         (click)="playState() === 'play' ? stop() : play()"
                     >
                         <mat-icon>{{
@@ -85,6 +105,10 @@ import { ChannelActions } from '@iptvnator/m3u-state';
                     <button
                         mat-icon-button
                         class="skip-btn"
+                        [matTooltip]="'AUDIO_PLAYER.NEXT_STATION' | translate"
+                        [attr.aria-label]="
+                            'AUDIO_PLAYER.NEXT_STATION' | translate
+                        "
                         (click)="switchChannel('next')"
                     >
                         <mat-icon>skip_next</mat-icon>
@@ -92,13 +116,38 @@ import { ChannelActions } from '@iptvnator/m3u-state';
                 </div>
 
                 <div class="volume-row">
-                    <button mat-icon-button class="vol-icon" (click)="mute()">
+                    <button
+                        mat-icon-button
+                        class="vol-icon"
+                        [matTooltip]="
+                            (isMuted() || volume() === 0
+                                ? 'AUDIO_PLAYER.UNMUTE'
+                                : 'AUDIO_PLAYER.MUTE'
+                            ) | translate
+                        "
+                        [attr.aria-label]="
+                            (isMuted() || volume() === 0
+                                ? 'AUDIO_PLAYER.UNMUTE'
+                                : 'AUDIO_PLAYER.MUTE'
+                            ) | translate
+                        "
+                        (click)="mute()"
+                    >
                         <mat-icon>{{ volumeIcon() }}</mat-icon>
                     </button>
-                    <mat-slider class="vol-slider" min="0" max="1" step="0.05">
+                    <mat-slider
+                        class="vol-slider"
+                        min="0"
+                        max="1"
+                        step="0.05"
+                        [matTooltip]="'AUDIO_PLAYER.VOLUME' | translate"
+                    >
                         <input
                             matSliderThumb
                             [ngModel]="volume()"
+                            [attr.aria-label]="
+                                'AUDIO_PLAYER.VOLUME' | translate
+                            "
                             (ngModelChange)="setVolume($event)"
                         />
                     </mat-slider>
@@ -109,7 +158,14 @@ import { ChannelActions } from '@iptvnator/m3u-state';
         </div>
     `,
     styleUrls: ['./audio-player.component.scss'],
-    imports: [MatSliderModule, MatIconModule, MatButtonModule, FormsModule],
+    imports: [
+        FormsModule,
+        MatButtonModule,
+        MatIconModule,
+        MatSliderModule,
+        MatTooltip,
+        TranslatePipe,
+    ],
 })
 export class AudioPlayerComponent {
     readonly icon = input<string>('');