i18n: complete internationalization for provider and usage query panels

- Add 45+ new translation keys for usage query and usage script features
- Fix duplicate provider object in translation files that caused missing translations
- Remove all hardcoded Chinese text and defaultValue fallbacks from components
- Add proper translations for:
  * Usage footer (query status, plan usage display)
  * Usage script modal (script editor, validation, test controls)
  * Provider forms (basic fields, endpoints, model selectors)
  * Provider dialogs (add/edit hints and titles)

Modified 16 files:
- 2 translation files (zh.json, en.json)
- 14 component files (removed defaultValue, added t() calls)

All UI text now properly supports Chinese/English switching.

src/i18n/locales/en.json

@@ -73,13 +73,15 @@
     "sortUpdateFailed": "Failed to update sort order",
     "configureUsage": "Configure usage query",
     "name": "Provider Name",
+    "namePlaceholder": "e.g., Claude Official",
     "websiteUrl": "Website URL",
     "configJson": "Config JSON",
     "writeCommonConfig": "Write common config",
     "editCommonConfigButton": "Edit common config",
     "configJsonHint": "Please fill in complete Claude Code configuration",
     "editCommonConfigTitle": "Edit common config snippet",
-    "editCommonConfigHint": "Common config snippet will be merged into all providers that enable it"
+    "editCommonConfigHint": "Common config snippet will be merged into all providers that enable it",
+    "addProvider": "Add Provider"
   },
   "notifications": {
     "providerSaved": "Provider configuration saved",
@@ -297,6 +299,48 @@
     "other": "Other",
     "hint": "You can continue to adjust the fields below after selecting a preset."
   },
+  "usage": {
+    "queryFailed": "Query failed",
+    "refreshUsage": "Refresh usage",
+    "planUsage": "Plan usage",
+    "invalid": "Expired",
+    "total": "Total:",
+    "used": "Used:",
+    "remaining": "Remaining:"
+  },
+  "usageScript": {
+    "title": "Configure Usage Query",
+    "enableUsageQuery": "Enable usage query",
+    "presetTemplate": "Preset template",
+    "queryScript": "Query script (JavaScript)",
+    "timeoutSeconds": "Timeout (seconds)",
+    "scriptHelp": "Script writing instructions:",
+    "configFormat": "Configuration format:",
+    "extractorFormat": "Extractor return format (all fields optional):",
+    "tips": "💡 Tips:",
+    "testing": "Testing...",
+    "testScript": "Test script",
+    "format": "Format",
+    "saveConfig": "Save config",
+    "scriptEmpty": "Script configuration cannot be empty",
+    "mustHaveReturn": "Script must contain return statement",
+    "testSuccess": "Test successful!",
+    "testFailed": "Test failed",
+    "formatSuccess": "Format successful",
+    "formatFailed": "Format failed",
+    "variablesHint": "Supported variables: {{apiKey}}, {{baseUrl}} | extractor function receives API response JSON object",
+    "fieldIsValid": "• isValid: Boolean, whether plan is valid",
+    "fieldInvalidMessage": "• invalidMessage: String, reason for expiration (shown when isValid is false)",
+    "fieldRemaining": "• remaining: Number, remaining quota",
+    "fieldUnit": "• unit: String, unit (e.g., \"USD\")",
+    "fieldPlanName": "• planName: String, plan name",
+    "fieldTotal": "• total: Number, total quota",
+    "fieldUsed": "• used: Number, used quota",
+    "fieldExtra": "• extra: String, custom display text",
+    "tip1": "• Variables {{apiKey}} and {{baseUrl}} are automatically replaced",
+    "tip2": "• Extractor function runs in sandbox environment, supports ES2020+ syntax",
+    "tip3": "• Entire config must be wrapped in () to form object literal expression"
+  },
   "kimiSelector": {
     "modelConfig": "Model Configuration",
     "mainModel": "Main Model",