feat(banners): rotate active banners one at a time with a pager

Stacking every active banner vertically ate header height when several
were active at once. Only the highest-priority banner renders now; a
‹ 1/N › pager cycles through the rest, and all active banners are still
recorded in the notification-center history so cycled-away ones stay
reachable. Newly registered banners preempt the displayed one only when
they outrank it.

Also fix the startup flow: the restart-required banner (now priority 80)
outranks the model-folders setup warning (60), and the setup banner is
retired once a non-empty folder path is saved.

New banners.pager.* keys translated in all 9 locales.

locales/de.json

@@ -2741,6 +2741,11 @@
             "content": "Scannen und verwalten Sie VAE-, Upscaler-, Text-Encoder-, CLIP-Vision- und ControlNet-Dateien und laden Sie sie von CivitAI herunter, alles auf einer eigenen Seite.",
             "enable": "Weitere Modelle aktivieren",
             "openSettings": "Einstellungen öffnen"
+        },
+        "pager": {
+            "previous": "Vorherige Mitteilung",
+            "next": "Nächste Mitteilung",
+            "position": "Mitteilung {current} von {total}"
         }
     }
 }

locales/en.json

@@ -2741,6 +2741,11 @@
       "content": "Scan and manage VAE, upscaler, text encoder, CLIP vision and ControlNet files — and download them from CivitAI — from one dedicated page.",
       "enable": "Enable Other Models",
       "openSettings": "Open Settings"
+    },
+    "pager": {
+      "previous": "Previous message",
+      "next": "Next message",
+      "position": "Message {current} of {total}"
     }
   }
 }

locales/es.json

@@ -2741,6 +2741,11 @@
             "content": "Escanea y gestiona archivos VAE, Upscaler, Text Encoder, CLIP Vision y ControlNet, y descárgalos desde CivitAI, todo desde una página dedicada.",
             "enable": "Activar otros modelos",
             "openSettings": "Abrir configuración"
+        },
+        "pager": {
+            "previous": "Notificación anterior",
+            "next": "Notificación siguiente",
+            "position": "Notificación {current} de {total}"
         }
     }
 }

locales/fr.json

@@ -2741,6 +2741,11 @@
             "content": "Analysez et gérez les fichiers VAE, Upscaler, Text Encoder, CLIP Vision et ControlNet, et téléchargez-les depuis CivitAI, le tout depuis une page dédiée.",
             "enable": "Activer les autres modèles",
             "openSettings": "Ouvrir les paramètres"
+        },
+        "pager": {
+            "previous": "Message précédent",
+            "next": "Message suivant",
+            "position": "Message {current} sur {total}"
         }
     }
 }

locales/he.json

@@ -2741,6 +2741,11 @@
             "content": "סרוק ונהל קבצי VAE, Upscaler, Text Encoder, CLIP Vision ו-ControlNet, והורד אותם מ-CivitAI — מהעמוד הייעודי.",
             "enable": "הפעל מודלים אחרים",
             "openSettings": "פתח הגדרות"
+        },
+        "pager": {
+            "previous": "הודעה קודמת",
+            "next": "הודעה הבאה",
+            "position": "הודעה {current} מתוך {total}"
         }
     }
 }

locales/ja.json

@@ -2741,6 +2741,11 @@
             "content": "専用ページで VAE、Upscaler、Text Encoder、CLIP Vision、ControlNet の各ファイルをスキャン・管理し、CivitAI からダウンロードできます。",
             "enable": "その他のモデルを有効にする",
             "openSettings": "設定を開く"
+        },
+        "pager": {
+            "previous": "前の通知",
+            "next": "次の通知",
+            "position": "{total} 件中 {current} 件目の通知"
         }
     }
 }

locales/ko.json

@@ -2741,6 +2741,11 @@
             "content": "전용 페이지에서 VAE, Upscaler, Text Encoder, CLIP Vision, ControlNet 파일을 스캔 및 관리하고 CivitAI에서 다운로드할 수 있습니다.",
             "enable": "기타 모델 활성화",
             "openSettings": "설정 열기"
+        },
+        "pager": {
+            "previous": "이전 알림",
+            "next": "다음 알림",
+            "position": "전체 {total}개 중 {current}번째 알림"
         }
     }
 }

locales/ru.json

@@ -2741,6 +2741,11 @@
             "content": "Сканирование и управление файлами VAE, Upscaler, Text Encoder, CLIP Vision и ControlNet, а также загрузка их с CivitAI — всё на одной отдельной странице.",
             "enable": "Включить другие модели",
             "openSettings": "Открыть настройки"
+        },
+        "pager": {
+            "previous": "Предыдущее уведомление",
+            "next": "Следующее уведомление",
+            "position": "Уведомление {current} из {total}"
         }
     }
 }

locales/zh-CN.json

@@ -2741,6 +2741,11 @@
             "content": "在一个专属页面中扫描和管理 VAE、Upscaler、Text Encoder、CLIP Vision 和 ControlNet 文件，并从 CivitAI 下载。",
             "enable": "启用其他模型",
             "openSettings": "打开设置"
+        },
+        "pager": {
+            "previous": "上一条通知",
+            "next": "下一条通知",
+            "position": "第 {current} 条通知，共 {total} 条"
         }
     }
 }

locales/zh-TW.json

@@ -2741,6 +2741,11 @@
             "content": "在專屬頁面中掃描和管理 VAE、Upscaler、Text Encoder、CLIP Vision 和 ControlNet 檔案，並從 CivitAI 下載。",
             "enable": "啟用其他模型",
             "openSettings": "開啟設定"
+        },
+        "pager": {
+            "previous": "上一則通知",
+            "next": "下一則通知",
+            "position": "第 {current} 則通知，共 {total} 則"
         }
     }
 }