docs: add VitePress documentation site

- Add docs directory with VitePress configuration
- Add GitHub Actions workflow for docs build and deploy
- Support bilingual (English/Chinese) documentation
- Include search, custom theme, and responsive design

docs/lighthouse-budget.json

@@ -0,0 +1,53 @@
+{
+  "budgets": [
+    {
+      "path": "/*",
+      "timings": [
+        {
+          "metric": "first-contentful-paint",
+          "budget": 2000
+        },
+        {
+          "metric": "interactive",
+          "budget": 5000
+        },
+        {
+          "metric": "speed-index",
+          "budget": 3400
+        },
+        {
+          "metric": "total-blocking-time",
+          "budget": 300
+        }
+      ],
+      "resourceSizes": [
+        {
+          "resourceType": "script",
+          "budget": 300
+        },
+        {
+          "resourceType": "stylesheet",
+          "budget": 100
+        },
+        {
+          "resourceType": "total",
+          "budget": 500
+        }
+      ],
+      "resourceCounts": [
+        {
+          "resourceType": "script",
+          "budget": 10
+        },
+        {
+          "resourceType": "stylesheet",
+          "budget": 5
+        },
+        {
+          "resourceType": "total",
+          "budget": 20
+        }
+      ]
+    }
+  ]
+}