feat(web): 主题皮肤系统与 LLM 设置面板重构

- useThemeSkin 重构主题皮肤应用逻辑，支持企业 AI 风格主题切换
- settingsModelHelper 新增主题与模型表字段映射，useSettings 适配
- LlmSettingsPanel/SettingsView 面板重构，支持多模型行编辑与主题区块
- settings-view.css 适配主题样式，新增 settings-theme-section 测试，更新 settings-llm-section 测试

web/tests/settings-llm-section.test.mjs

@@ -7,17 +7,27 @@ const llmSettingsPanel = readFileSync(new URL('../src/views/LlmSettingsPanel.vue
 
 function testLlmSectionReplacesVlmWithReranker() {
   assert.doesNotMatch(settingsView, /VLM 模型/)
-  assert.match(llmSettingsPanel, /Reranker 模型配置/)
+  assert.match(llmSettingsPanel, /Rerank/)
   assert.match(settingsModel, /rerankerProvider/)
 }
 
-function testRerankerCardRendersAfterEmbeddingCard() {
-  assert.match(llmSettingsPanel, /Embedding 模型配置[\s\S]*Reranker 模型配置/)
+function testLlmSectionUsesTableAndAddModelDialog() {
+  assert.match(llmSettingsPanel, /model-table-toolbar[\s\S]*添加模型/)
+  assert.match(llmSettingsPanel, /<table class="model-config-table">/)
+  assert.match(llmSettingsPanel, /model-dialog-overlay/)
+  assert.match(llmSettingsPanel, /供应商[\s\S]*接口地址[\s\S]*API Key[\s\S]*model_id[\s\S]*模型类型/)
+  assert.match(llmSettingsPanel, /大语言模型[\s\S]*Embedding[\s\S]*Rerank/)
+}
+
+function testSettingsModelKeepsExtensibleModelRows() {
+  assert.match(settingsModel, /models:\s*buildLlmModelRows/)
+  assert.match(settingsModel, /buildLlmModelRows/)
 }
 
 function run() {
   testLlmSectionReplacesVlmWithReranker()
-  testRerankerCardRendersAfterEmbeddingCard()
+  testLlmSectionUsesTableAndAddModelDialog()
+  testSettingsModelKeepsExtensibleModelRows()
   console.log('settings llm section tests passed')
 }