fix: 修复 .gitignore 并降级 React 到 18 以对齐设计文档

- 补充 .gitignore：忽略 node_modules/、dist/、bin/、.env、.obsidian/ 等
- 降级 react、react-dom 到 18.3.1，@types/react、@types/react-dom 到 18.x
- 与 docs/02-系统架构.md 和 CLAUDE.md 中的 React 18 技术选型保持一致

Co-Authored-By: Claude <noreply@anthropic.com>

frontend/package-lock.json

@@ -10,15 +10,15 @@
       "dependencies": {
         "@ricky0123/vad-web": "^0.0.30",
         "onnxruntime-web": "^1.26.0",
-        "react": "^19.2.6",
-        "react-dom": "^19.2.6",
+        "react": "^18.3.1",
+        "react-dom": "^18.3.1",
         "uuid": "^14.0.0"
       },
       "devDependencies": {
         "@eslint/js": "^10.0.1",
         "@types/node": "^24.12.3",
-        "@types/react": "^19.2.14",
-        "@types/react-dom": "^19.2.3",
+        "@types/react": "^18.3.31",
+        "@types/react-dom": "^18.3.7",
         "@types/uuid": "^10.0.0",
         "@vitejs/plugin-react": "^6.0.1",
         "eslint": "^10.3.0",
@@ -954,24 +954,32 @@
         "undici-types": "~7.18.0"
       }
     },
+    "node_modules/@types/prop-types": {
+      "version": "15.7.15",
+      "resolved": "https://registry.npmjs.org/@types/prop-types/-/prop-types-15.7.15.tgz",
+      "integrity": "sha512-F6bEyamV9jKGAFBEmlQnesRPGOQqS2+Uwi0Em15xenOxHaf2hv6L8YCVn3rPdPJOiJfPiCnLIRyvwVaqMY3MIw==",
+      "dev": true,
+      "license": "MIT"
+    },
     "node_modules/@types/react": {
-      "version": "19.2.17",
-      "resolved": "https://registry.npmjs.org/@types/react/-/react-19.2.17.tgz",
-      "integrity": "sha512-MXfmqaVPEVgkBT/aY0aGCkRWWtByiYQXo3xdQ8r5RzuFrPiRn8Gar2tQdXSUQ2GKV3bkXckek89V8wQBY2Q/Aw==",
+      "version": "18.3.31",
+      "resolved": "https://registry.npmjs.org/@types/react/-/react-18.3.31.tgz",
+      "integrity": "sha512-vfEqpXTvwT91yhmwdfouStN2hSKwTvyRs8qpLfADyrq/kxDw0hZM7Wk9Ug1FELj8hIby+S/+kQCSRFF32nv2Qw==",
       "dev": true,
       "license": "MIT",
       "dependencies": {
+        "@types/prop-types": "*",
         "csstype": "^3.2.2"
       }
     },
     "node_modules/@types/react-dom": {
-      "version": "19.2.3",
-      "resolved": "https://registry.npmjs.org/@types/react-dom/-/react-dom-19.2.3.tgz",
-      "integrity": "sha512-jp2L/eY6fn+KgVVQAOqYItbF0VY/YApe5Mz2F0aykSO8gx31bYCZyvSeYxCHKvzHG5eZjc+zyaS5BrBWya2+kQ==",
+      "version": "18.3.7",
+      "resolved": "https://registry.npmjs.org/@types/react-dom/-/react-dom-18.3.7.tgz",
+      "integrity": "sha512-MEe3UeoENYVFXzoXEWsvcpg6ZvlrFNlOQ7EOsvhI3CfAXwzPfO8Qwuxd40nepsYKqyyVQnTdEfv68q91yLcKrQ==",
       "dev": true,
       "license": "MIT",
       "peerDependencies": {
-        "@types/react": "^19.2.0"
+        "@types/react": "^18.0.0"
       }
     },
     "node_modules/@types/uuid": {
@@ -1881,7 +1889,6 @@
       "version": "4.0.0",
       "resolved": "https://registry.npmjs.org/js-tokens/-/js-tokens-4.0.0.tgz",
       "integrity": "sha512-RdJUflcE3cUzKiMqQgsCu06FPu9UdIJO0beYbPhHN4k6apgJtifcoCtT9bcxOpYBtpD2kCM6Sbzg4CausW/PKQ==",
-      "dev": true,
       "license": "MIT"
     },
     "node_modules/jsesc": {
@@ -2238,6 +2245,18 @@
       "integrity": "sha512-mNAgZ1GmyNhD7AuqnTG3/VQ26o760+ZYBPKjPvugO8+nLbYfX6TVpJPseBvopbdY+qpZ/lKUnmEc1LeZYS3QAA==",
       "license": "Apache-2.0"
     },
+    "node_modules/loose-envify": {
+      "version": "1.4.0",
+      "resolved": "https://registry.npmjs.org/loose-envify/-/loose-envify-1.4.0.tgz",
+      "integrity": "sha512-lyuxPGr/Wfhrlem2CL/UcnUc1zcqKAImBDzukY7Y5F/yQiNdko6+fRLevlw1HgMySw7f611UIY408EtxRSoK3Q==",
+      "license": "MIT",
+      "dependencies": {
+        "js-tokens": "^3.0.0 || ^4.0.0"
+      },
+      "bin": {
+        "loose-envify": "cli.js"
+      }
+    },
     "node_modules/lru-cache": {
       "version": "5.1.1",
       "resolved": "https://registry.npmjs.org/lru-cache/-/lru-cache-5.1.1.tgz",
@@ -2497,24 +2516,28 @@
       }
     },
     "node_modules/react": {
-      "version": "19.2.7",
-      "resolved": "https://registry.npmjs.org/react/-/react-19.2.7.tgz",
-      "integrity": "sha512-HNe9WslTbXmFK8o8cmwgAeJFSBvt1bPdHCVKtaaV+WlAN36mpT4hcRpwbf3fY56ar2oIXzsBpOAiIRHAdY0OlQ==",
+      "version": "18.3.1",
+      "resolved": "https://registry.npmjs.org/react/-/react-18.3.1.tgz",
+      "integrity": "sha512-wS+hAgJShR0KhEvPJArfuPVN1+Hz1t0Y6n5jLrGQbkb4urgPE/0Rve+1kMB1v/oWgHgm4WIcV+i7F2pTVj+2iQ==",
       "license": "MIT",
+      "dependencies": {
+        "loose-envify": "^1.1.0"
+      },
       "engines": {
         "node": ">=0.10.0"
       }
     },
     "node_modules/react-dom": {
-      "version": "19.2.7",
-      "resolved": "https://registry.npmjs.org/react-dom/-/react-dom-19.2.7.tgz",
-      "integrity": "sha512-t0BRVXvbiE/o20Hfw669rLbMCDWtYZLvmJigy2f0MxsXF+71pxhR3xOkspmsO8h3ZlNzyibAmtCa3l4lYKk6gQ==",
+      "version": "18.3.1",
+      "resolved": "https://registry.npmjs.org/react-dom/-/react-dom-18.3.1.tgz",
+      "integrity": "sha512-5m4nQKp+rZRb09LNH59GM4BxTh9251/ylbKIbpe7TpGxfJ+9kv6BLkLBXIjjspbgbnIBNqlI23tRnTWT0snUIw==",
       "license": "MIT",
       "dependencies": {
-        "scheduler": "^0.27.0"
+        "loose-envify": "^1.1.0",
+        "scheduler": "^0.23.2"
       },
       "peerDependencies": {
-        "react": "^19.2.7"
+        "react": "^18.3.1"
       }
     },
     "node_modules/rolldown": {
@@ -2552,10 +2575,13 @@
       }
     },
     "node_modules/scheduler": {
-      "version": "0.27.0",
-      "resolved": "https://registry.npmjs.org/scheduler/-/scheduler-0.27.0.tgz",
-      "integrity": "sha512-eNv+WrVbKu1f3vbYJT/xtiF5syA5HPIMtf9IgY/nKg0sWqzAUEvqY/xm7OcZc/qafLx/iO9FgOmeSAp4v5ti/Q==",
-      "license": "MIT"
+      "version": "0.23.2",
+      "resolved": "https://registry.npmjs.org/scheduler/-/scheduler-0.23.2.tgz",
+      "integrity": "sha512-UOShsPwz7NrMUqhR6t0hWjFduvOzbtv7toDH1/hIrfRNIDBnnBWd0CwJTGvTpngVlmwGCdP9/Zl/tVrDqcuYzQ==",
+      "license": "MIT",
+      "dependencies": {
+        "loose-envify": "^1.1.0"
+      }
     },
     "node_modules/semver": {
       "version": "6.3.1",