feat: redesign LineSegmentFlow + dev improvements

- LineSegmentFlow: LobeHub brand icons, concave left curves, glow effects
- Dark mode: line colors adapt, animated lines glow in dark theme
- Vite: enable LAN access (host: 0.0.0.0)
- VSCode: workspace settings for performance optimization
- Toast: redesign with icons, progress bar, better animations

.vscode/settings.json

@@ -0,0 +1,40 @@
+{
+  // Vue: 启用 Take Over 模式，禁用内置 TS 服务，减少内存占用
+  "vue.server.hybridMode": true,
+
+  // Git: 降低自动拉取频率
+  "git.autofetch": false,
+  "git.maxVisibleCommits": 10,
+  "git.decorations.enabled": false,
+
+  // 保存时只格式化，不运行 code action（慢）
+  "editor.formatOnSave": true,
+  "editor.codeActionsOnSave": {
+    "source.fixAll.eslint": "never",
+    "source.organizeImports": "never"
+  },
+
+  // 排除大目录，减少文件监听
+  "files.watcherExclude": {
+    "**/node_modules/**": true,
+    "**/.git/objects/**": true,
+    "**/dist/**": true,
+    "**/tmp/**": true,
+    "**/bin/**": true
+  },
+
+  // 排除搜索目录
+  "search.exclude": {
+    "**/node_modules": true,
+    "**/dist": true,
+    "**/tmp": true,
+    "**/bin": true,
+    "**/*.sum": true
+  },
+
+  // TypeScript: 降低语言服务开销
+  "typescript.tsserver.maxTsServerMemory": 1024,
+  "typescript.tsserver.watchOptions": {
+    "excludeDirectories": ["node_modules", "dist"]
+  }
+}