Enhance DeviceContext and LuxsinAPI to support new PEQ apply functionality; update locale files for English and Chinese to include new UI strings for applying and saving PEQ settings. Refactor AudioPage and EQPage to integrate boot sound management and improve state handling.

client/src/locales/data-en.json

@@ -283,9 +283,14 @@
       "errFilterNumbers": "Invalid numbers for filter {{no}}",
       "errFilterAll": "Filters 1–10 must all be present",
       "chartCopyTo": "Copy to {{mode}}",
-      "chartLoadToDevice": "Load to device",
+      "chartApplyB": "Apply B",
+      "chartSaveB": "Save B As",
+      "saveBTitle": "Save B As",
       "toastChartCopied": "Copied to {{mode}}",
-      "toastChartLoadedDevice": "Loaded to device"
+      "toastApplyBSuccess": "Curve B applied to A",
+      "toastApplyBFail": "Failed to apply B",
+      "toastSaveBOk": "Preset saved from curve B",
+      "toastSaveBFail": "Failed to save curve B"
     }
   },
   "dac": {
@@ -341,7 +346,22 @@
       ]
     },
     "volumeStep": "Volume step",
-    "bootVolume": "Boot volume",
+    "bootVolume": {
+      "label": "Boot volume",
+      "options": [
+        { "index": 0, "label": "Default" },
+        { "index": 1, "label": "-5dB" },
+        { "index": 2, "label": "-10dB" },
+        { "index": 3, "label": "-15dB" },
+        { "index": 4, "label": "-20dB" },
+        { "index": 5, "label": "-25dB" },
+        { "index": 6, "label": "-30dB" },
+        { "index": 7, "label": "-35dB" },
+        { "index": 8, "label": "-40dB" },
+        { "index": 9, "label": "-45dB" },
+        { "index": 10, "label": "-50dB" }
+      ]
+    },
     "xlr": {
       "label": "XLR port polarity",
       "options": [