feat: implement localization for models section

- Added a new copy module to handle translations for models-related components.
- Integrated translation functionality into ProviderPickerDialog, ProvidersSection, RequestContentDialog, UsageBarChart, and UsageHistorySection.
- Updated messages for various UI elements to support multiple languages.
- Refactored usage history functions to accept locale for date formatting.
- Enhanced user experience by providing localized strings for success/error messages and UI labels.

src/lib/providers.ts

@@ -1,3 +1,5 @@
+import type { LanguageCode } from '../types/runtime';
+
 export const PROVIDER_TYPES = [
   'anthropic',
   'openai',
@@ -57,6 +59,8 @@ export interface ProviderTypeInfo {
   name: string;
   icon: string;
   placeholder: string;
+  placeholderZh?: string;
+  placeholderJa?: string;
   model?: string;
   requiresApiKey: boolean;
   defaultBaseUrl?: string;
@@ -167,12 +171,14 @@ export const PROVIDER_TYPE_INFO: ProviderTypeInfo[] = [
   { id: 'minimax-portal', name: 'MiniMax (Global)', icon: '☁️', placeholder: 'sk-...', model: 'MiniMax', requiresApiKey: false, isOAuth: true, supportsApiKey: true, defaultModelId: 'MiniMax-M2.7', showModelId: true, showModelIdInDevModeOnly: true, modelIdPlaceholder: 'MiniMax-M2.7', apiKeyUrl: 'https://platform.minimax.io' },
   { id: 'modelstudio', name: 'Model Studio', icon: '☁️', placeholder: 'sk-...', model: 'Qwen', requiresApiKey: true, defaultBaseUrl: 'https://coding.dashscope.aliyuncs.com/v1', showBaseUrl: true, defaultModelId: 'qwen3.5-plus', showModelId: true, showModelIdInDevModeOnly: true, modelIdPlaceholder: 'qwen3.5-plus', apiKeyUrl: 'https://bailian.console.aliyun.com/', hidden: true },
   { id: 'ark', name: 'ByteDance Ark', icon: 'A', placeholder: 'your-ark-api-key', model: 'Doubao', requiresApiKey: true, defaultBaseUrl: 'https://ark.cn-beijing.volces.com/api/v3', showBaseUrl: true, showModelId: true, modelIdPlaceholder: 'ep-20260228000000-xxxxx', docsUrl: 'https://www.volcengine.com/', codePlanPresetBaseUrl: 'https://ark.cn-beijing.volces.com/api/coding/v3', codePlanPresetModelId: 'ark-code-latest', codePlanDocsUrl: 'https://www.volcengine.com/docs/82379/1928261?lang=zh' },
-  { id: 'ollama', name: 'Ollama', icon: '🦙', placeholder: 'Not required', requiresApiKey: false, defaultBaseUrl: 'http://localhost:11434/v1', showBaseUrl: true, showModelId: true, modelIdPlaceholder: 'qwen3:latest' },
+  { id: 'ollama', name: 'Ollama', icon: '🦙', placeholder: 'Not required', placeholderZh: '无需填写', placeholderJa: '不要', requiresApiKey: false, defaultBaseUrl: 'http://localhost:11434/v1', showBaseUrl: true, showModelId: true, modelIdPlaceholder: 'qwen3:latest' },
   {
     id: 'custom',
     name: 'Custom',
     icon: '⚙️',
     placeholder: 'API key...',
+    placeholderZh: 'API Key...',
+    placeholderJa: 'API キー...',
     requiresApiKey: true,
     showBaseUrl: true,
     showModelId: true,
@@ -198,7 +204,7 @@ export function getProviderTypeInfo(type: ProviderType): ProviderTypeInfo | unde
 
 export function getProviderDocsUrl(
   provider: Pick<ProviderTypeInfo, 'docsUrl' | 'docsUrlZh'> | undefined,
-  language: string,
+  language: string | LanguageCode,
 ): string | undefined {
   if (!provider?.docsUrl) {
     return undefined;
@@ -209,6 +215,22 @@ export function getProviderDocsUrl(
   return provider.docsUrl;
 }
 
+export function getProviderPlaceholder(
+  provider: Pick<ProviderTypeInfo, 'placeholder' | 'placeholderZh' | 'placeholderJa'> | undefined,
+  language: string | LanguageCode,
+): string | undefined {
+  if (!provider?.placeholder) {
+    return undefined;
+  }
+  if (language.startsWith('zh') && provider.placeholderZh) {
+    return provider.placeholderZh;
+  }
+  if (language.startsWith('ja') && provider.placeholderJa) {
+    return provider.placeholderJa;
+  }
+  return provider.placeholder;
+}
+
 export function shouldShowProviderModelId(
   provider: Pick<ProviderTypeInfo, 'showModelId' | 'showModelIdInDevModeOnly'> | undefined,
   devModeUnlocked: boolean,