feat: add category-specific hints to provider form

- Add dynamic hint text based on provider category (official, opensource, aggregator, third-party, custom)
- Display hints in ProviderPresetSelector below preset buttons
- Rename "Chinese official" to "Opensource official" for better clarity
- Add i18n keys for all category hints in both zh and en locales
- Remove redundant hint boxes from ClaudeFormFields and CodexFormFields

This improves user guidance by showing contextual hints that explain
what fields are required for each provider category.

src/i18n/locales/zh.json

@@ -211,6 +211,11 @@
     "codexApiKeyAutoFill": "只需要填这里，下方 auth.json 会自动填充",
     "kimiApiKeyHint": "填写后可获取模型列表",
     "apiKeyAutoFill": "只需要填这里，下方配置会自动填充",
+    "cnOfficialApiKeyHint": "💡 开源官方供应商只需填写 API Key，请求地址已预设",
+    "aggregatorApiKeyHint": "💡 聚合服务供应商只需填写 API Key 即可使用",
+    "thirdPartyApiKeyHint": "💡 第三方供应商需要填写 API Key 和请求地址",
+    "customApiKeyHint": "💡 自定义配置需手动填写所有必要字段",
+    "officialHint": "💡 官方供应商使用浏览器登录，无需配置 API Key",
     "getApiKey": "获取 API Key",
     "parameterConfig": "参数配置 - {{name}} *",
     "mainModel": "主模型 (可选)",
@@ -236,7 +241,7 @@
     "smallModelPlaceholder": "claude-3-5-haiku-20241022",
     "modelHelper": "可选：指定默认使用的 Claude 模型，留空则使用系统默认。",
     "categoryOfficial": "官方",
-    "categoryCnOfficial": "国内官方",
+    "categoryCnOfficial": "开源官方",
     "categoryAggregation": "聚合服务",
     "categoryThirdParty": "第三方"
   },