🌐(i18n) add PiP accessibility strings to rooms

Labels for PiP window, stage, toolbar, reactions, and SR open/close.

src/frontend/src/locales/de/rooms.json

@@ -243,7 +243,14 @@
       "switchCamera": "Kamera wechseln",
       "pictureInPicture": {
         "enter": "Bild-im-Bild",
-        "exit": "Bild-im-Bild schließen"
+        "exit": "Bild-im-Bild schließen",
+        "opened": "Bild-im-Bild-Modus aktiviert",
+        "closed": "Bild-im-Bild-Modus deaktiviert",
+        "windowLabel": "Bild-im-Bild Besprechung",
+        "stage": "Teilnehmer",
+        "controlBar": "Besprechungssteuerung",
+        "previousReactions": "Vorherige Reaktionen",
+        "nextReactions": "Nächste Reaktionen"
       },
       "fullscreen": {
         "enter": "Vollbild",

src/frontend/src/locales/en/rooms.json

@@ -243,7 +243,14 @@
       "switchCamera": "Switch camera",
       "pictureInPicture": {
         "enter": "Picture-in-picture",
-        "exit": "Close picture-in-picture"
+        "exit": "Close picture-in-picture",
+        "opened": "Picture-in-picture mode enabled",
+        "closed": "Picture-in-picture mode disabled",
+        "windowLabel": "Picture-in-picture meeting",
+        "stage": "Participants",
+        "controlBar": "Meeting controls",
+        "previousReactions": "Previous reactions",
+        "nextReactions": "Next reactions"
       },
       "fullscreen": {
         "enter": "Fullscreen",

src/frontend/src/locales/fr/rooms.json

@@ -243,7 +243,14 @@
       "switchCamera": "Changer de caméra",
       "pictureInPicture": {
         "enter": "Image dans l'image",
-        "exit": "Fermer l'image dans l'image"
+        "exit": "Fermer l'image dans l'image",
+        "opened": "Mode image dans l'image activé",
+        "closed": "Mode image dans l'image désactivé",
+        "windowLabel": "Réunion en image dans l'image",
+        "stage": "Participants",
+        "controlBar": "Commandes de la réunion",
+        "previousReactions": "Réactions précédentes",
+        "nextReactions": "Réactions suivantes"
       },
       "fullscreen": {
         "enter": "Plein écran",

src/frontend/src/locales/nl/rooms.json

@@ -243,7 +243,14 @@
       "switchCamera": "Selecteer camera",
       "pictureInPicture": {
         "enter": "Beeld-in-beeld",
-        "exit": "Beeld-in-beeld sluiten"
+        "exit": "Beeld-in-beeld sluiten",
+        "opened": "Beeld-in-beeld-modus ingeschakeld",
+        "closed": "Beeld-in-beeld-modus uitgeschakeld",
+        "windowLabel": "Beeld-in-beeld vergadering",
+        "stage": "Deelnemers",
+        "controlBar": "Vergaderbesturing",
+        "previousReactions": "Vorige reacties",
+        "nextReactions": "Volgende reacties"
       },
       "fullscreen": {
         "enter": "Volledig scherm",