feat(skill-editor): implement file tree, tab management, and dirty state tracking

Implement MVP features for skill editor based on design doc:
- Add Zustand store with Tab, FileTree, and Dirty slices
- Rewrite file tree using react-arborist for virtual scrolling
- Implement Tab↔FileTree sync with auto-reveal on tab activation
- Add upload functionality (new folder, upload file)
- Implement Monaco editor with dirty state tracking and Ctrl+S save
- Add i18n translations (en-US and zh-Hans)

web/pnpm-lock.yaml

@@ -267,6 +267,9 @@ importers:
       react-18-input-autosize:
         specifier: ^3.0.0
         version: 3.0.0(react@19.2.3)
+      react-arborist:
+        specifier: ^3.4.3
+        version: 3.4.3(@types/node@18.15.0)(@types/react@19.2.7)(react-dom@19.2.3(react@19.2.3))(react@19.2.3)
       react-dom:
         specifier: 19.2.3
         version: 19.2.3(react@19.2.3)
@@ -2790,6 +2793,15 @@ packages:
       react: ^16.8.0 || ^17.0.0-rc.1 || ^18.0.0 || ^19.0.0-rc.1
       react-dom: ^16.8.0 || ^17.0.0-rc.1 || ^18.0.0 || ^19.0.0-rc.1
 
+  '@react-dnd/asap@4.0.1':
+    resolution: {integrity: sha512-kLy0PJDDwvwwTXxqTFNAAllPHD73AycE9ypWeln/IguoGBEbvFcPDbCV03G52bEcC5E+YgupBE0VzHGdC8SIXg==}
+
+  '@react-dnd/invariant@2.0.0':
+    resolution: {integrity: sha512-xL4RCQBCBDJ+GRwKTFhGUW8GXa4yoDfJrPbLblc3U09ciS+9ZJXJ3Qrcs/x2IODOdIE5kQxvMmE2UKyqUictUw==}
+
+  '@react-dnd/shallowequal@2.0.0':
+    resolution: {integrity: sha512-Pc/AFTdwZwEKJxFJvlxrSmGe/di+aAOBn60sremrpLo6VI/6cmiUYNNwlI5KNYttg7uypzA3ILPMPgxB2GYZEg==}
+
   '@react-stately/flags@3.1.2':
     resolution: {integrity: sha512-2HjFcZx1MyQXoPqcBGALwWWmgFVUk2TuKVIQxCbRq7fPyWXIl6VHcakCLurdtYC2Iks7zizvz0Idv48MQ38DWg==}
 
@@ -4927,6 +4939,9 @@ packages:
   dlv@1.1.3:
     resolution: {integrity: sha512-+HlytyjlPKnIG8XuRG8WvmBP8xs8P71y+SKKS6ZXWoEgLuePxtDoUEiH7WkdePWrQ5JBpE6aoVqfZfJUQkjXwA==}
 
+  dnd-core@14.0.1:
+    resolution: {integrity: sha512-+PVS2VPTgKFPYWo3vAFEA8WPbTf7/xo43TifH9G8S1KqnrQu0o77A3unrF5yOugy4mIz7K5wAVFHUcha7wsz6A==}
+
   doctrine@3.0.0:
     resolution: {integrity: sha512-yS+Q5i3hBf7GBkd4KG8a7eBNNWNGLTaEwwYWUijIYM7zrlYDM0BFXHjjPWlWZ1Rg7UaddZeIDmi9jF3HmqiQ2w==}
     engines: {node: '>=6.0.0'}
@@ -7157,6 +7172,30 @@ packages:
     peerDependencies:
       react: ^16.3.0 || ^17.0.0 || ^18.0.0
 
+  react-arborist@3.4.3:
+    resolution: {integrity: sha512-yFnq1nIQhT2uJY4TZVz2tgAiBb9lxSyvF4vC3S8POCK8xLzjGIxVv3/4dmYquQJ7AHxaZZArRGHiHKsEewKdTQ==}
+    peerDependencies:
+      react: '>= 16.14'
+      react-dom: '>= 16.14'
+
+  react-dnd-html5-backend@14.1.0:
+    resolution: {integrity: sha512-6ONeqEC3XKVf4eVmMTe0oPds+c5B9Foyj8p/ZKLb7kL2qh9COYxiBHv3szd6gztqi/efkmriywLUVlPotqoJyw==}
+
+  react-dnd@14.0.5:
+    resolution: {integrity: sha512-9i1jSgbyVw0ELlEVt/NkCUkxy1hmhJOkePoCH713u75vzHGyXhPDm28oLfc2NMSBjZRM1Y+wRjHXJT3sPrTy+A==}
+    peerDependencies:
+      '@types/hoist-non-react-statics': '>= 3.3.1'
+      '@types/node': '>= 12'
+      '@types/react': ~19.2.7
+      react: '>= 16.14'
+    peerDependenciesMeta:
+      '@types/hoist-non-react-statics':
+        optional: true
+      '@types/node':
+        optional: true
+      '@types/react':
+        optional: true
+
   react-docgen-typescript@2.4.0:
     resolution: {integrity: sha512-ZtAp5XTO5HRzQctjPU0ybY0RRCQO19X/8fxn3w7y2VVTUbGHDKULPTL4ky3vB05euSgG5NpALhEhDPvQ56wvXg==}
     peerDependencies:
@@ -7390,6 +7429,12 @@ packages:
     resolution: {integrity: sha512-6tDA8g98We0zd0GvVeMT9arEOnTw9qM03L9cJXaCjrip1OO764RDBLBfrB4cwzNGDj5OA5ioymC9GkizgWJDUg==}
     engines: {node: '>=8'}
 
+  redux@4.2.1:
+    resolution: {integrity: sha512-LAUYz4lc+Do8/g7aeRa8JkyDErK6ekstQaqWQrNRW//MY1TvCEpMtpTWvlQ+FPbWCx+Xixu/6SHt5N0HR+SB4w==}
+
+  redux@5.0.1:
+    resolution: {integrity: sha512-M9/ELqF6fy8FwmkpnF0S3YKOqMyoWJ4+CS5Efg2ct3oY9daQvd/Pc71FpGZsVsbl3Cpb+IIcjBDUnnyBdQbq4w==}
+
   refa@0.12.1:
     resolution: {integrity: sha512-J8rn6v4DBb2nnFqkqwy6/NnTYMcgLA+sLr0iIO41qpv0n+ngb7ksag2tMRl0inb1bbO/esUwzW1vbJi7K0sI0g==}
     engines: {node: ^12.0.0 || ^14.0.0 || >=16.0.0}
@@ -11114,6 +11159,12 @@ snapshots:
       react: 19.2.3
       react-dom: 19.2.3(react@19.2.3)
 
+  '@react-dnd/asap@4.0.1': {}
+
+  '@react-dnd/invariant@2.0.0': {}
+
+  '@react-dnd/shallowequal@2.0.0': {}
+
   '@react-stately/flags@3.1.2':
     dependencies:
       '@swc/helpers': 0.5.17
@@ -13532,6 +13583,12 @@ snapshots:
 
   dlv@1.1.3: {}
 
+  dnd-core@14.0.1:
+    dependencies:
+      '@react-dnd/asap': 4.0.1
+      '@react-dnd/invariant': 2.0.0
+      redux: 4.2.1
+
   doctrine@3.0.0:
     dependencies:
       esutils: 2.0.3
@@ -16333,6 +16390,36 @@ snapshots:
       prop-types: 15.8.1
       react: 19.2.3
 
+  react-arborist@3.4.3(@types/node@18.15.0)(@types/react@19.2.7)(react-dom@19.2.3(react@19.2.3))(react@19.2.3):
+    dependencies:
+      react: 19.2.3
+      react-dnd: 14.0.5(@types/node@18.15.0)(@types/react@19.2.7)(react@19.2.3)
+      react-dnd-html5-backend: 14.1.0
+      react-dom: 19.2.3(react@19.2.3)
+      react-window: 1.8.11(react-dom@19.2.3(react@19.2.3))(react@19.2.3)
+      redux: 5.0.1
+      use-sync-external-store: 1.6.0(react@19.2.3)
+    transitivePeerDependencies:
+      - '@types/hoist-non-react-statics'
+      - '@types/node'
+      - '@types/react'
+
+  react-dnd-html5-backend@14.1.0:
+    dependencies:
+      dnd-core: 14.0.1
+
+  react-dnd@14.0.5(@types/node@18.15.0)(@types/react@19.2.7)(react@19.2.3):
+    dependencies:
+      '@react-dnd/invariant': 2.0.0
+      '@react-dnd/shallowequal': 2.0.0
+      dnd-core: 14.0.1
+      fast-deep-equal: 3.1.3
+      hoist-non-react-statics: 3.3.2
+      react: 19.2.3
+    optionalDependencies:
+      '@types/node': 18.15.0
+      '@types/react': 19.2.7
+
   react-docgen-typescript@2.4.0(typescript@5.9.3):
     dependencies:
       typescript: 5.9.3
@@ -16634,6 +16721,12 @@ snapshots:
       indent-string: 4.0.0
       strip-indent: 3.0.0
 
+  redux@4.2.1:
+    dependencies:
+      '@babel/runtime': 7.28.4
+
+  redux@5.0.1: {}
+
   refa@0.12.1:
     dependencies:
       '@eslint-community/regexpp': 4.12.1