feat: add Ampcode (Amp CLI Integration) support with configuration UI and i18n

- Add ampcodeApi service for upstream URL, API key, and model mappings management
  - Implement Ampcode configuration modal in AiProvidersPage
  - Add complete i18n translations for Ampcode features (en and zh-CN)
  - Enhance UsagePage with mobile-responsive chart improvements and legend display
  - Optimize chart rendering for smaller screens
  - Improve page layout styles (SystemPage, AiProvidersPage alignment)

src/i18n/locales/zh-CN.json

@@ -24,6 +24,7 @@
     "disconnected_status": "未连接",
     "yes": "是",
     "no": "否",
+    "not_set": "未设置",
     "optional": "可选",
     "required": "必填",
     "api_key": "密钥",
@@ -185,6 +186,28 @@
     "claude_models_hint": "为空表示使用全部模型；可填写 name[, alias] 以限制或重命名模型。",
     "claude_models_add_btn": "添加模型",
     "claude_models_count": "模型数量",
+    "ampcode_title": "Amp CLI 集成 (ampcode)",
+    "ampcode_modal_title": "配置 Ampcode",
+    "ampcode_upstream_url_label": "Upstream URL",
+    "ampcode_upstream_url_placeholder": "例如: https://ampcode.com",
+    "ampcode_upstream_url_hint": "可选；留空表示使用默认/自动发现的控制平面地址。",
+    "ampcode_upstream_api_key_label": "Upstream API Key (Amp官方)",
+    "ampcode_upstream_api_key_placeholder": "输入 sk-amp...（留空不修改）",
+    "ampcode_upstream_api_key_hint": "可选；留空不会修改当前Amp官方密钥，需清除请点击下方按钮。",
+    "ampcode_upstream_api_key_current": "当前Amp官方密钥: {{key}}",
+    "ampcode_clear_upstream_api_key": "清除官方密钥",
+    "ampcode_clear_upstream_api_key_confirm": "确定要清除 Ampcode 的 upstream API key（Amp官方）吗？",
+    "ampcode_restrict_management_label": "仅允许本机访问 Amp 管理路由",
+    "ampcode_restrict_management_hint": "开启后，/api/auth、/api/user、/api/threads 等 Amp 管理路由仅允许 127.0.0.1/::1 访问（推荐）。",
+    "ampcode_force_model_mappings_label": "强制应用模型映射",
+    "ampcode_force_model_mappings_hint": "开启后，模型映射将覆盖本地 API Key 可用性判断。",
+    "ampcode_model_mappings_label": "模型映射 (from → to)",
+    "ampcode_model_mappings_hint": "用于重写 Amp 请求中的模型名称；留空表示不做映射。",
+    "ampcode_model_mappings_add_btn": "添加映射",
+    "ampcode_model_mappings_from_placeholder": "from 模型（原始）",
+    "ampcode_model_mappings_to_placeholder": "to 模型（目标）",
+    "ampcode_model_mappings_count": "映射数量",
+    "ampcode_mappings_overwrite_confirm": "当前未成功加载服务器已有映射，继续保存可能覆盖或清空已有映射，是否继续？",
     "openai_title": "OpenAI 兼容提供商",
     "openai_add_button": "添加提供商",
     "openai_empty_title": "暂无OpenAI兼容提供商",
@@ -618,6 +641,8 @@
     "openai_provider_added": "OpenAI提供商添加成功",
     "openai_provider_updated": "OpenAI提供商更新成功",
     "openai_provider_deleted": "OpenAI提供商删除成功",
+    "ampcode_updated": "Ampcode 配置已更新",
+    "ampcode_upstream_api_key_cleared": "Ampcode upstream API key 覆盖已清除",
     "openai_model_name_required": "请填写模型名称",
     "openai_test_url_required": "请先填写有效的 Base URL 以进行测试",
     "openai_test_key_required": "请至少填写一个 API 密钥以进行测试",