chore(ui): migrate vite 6 → 8, plugin-react 4 → 6; cache UI build in CI

.github/actions/build-ui/action.yml

@@ -0,0 +1,38 @@
+name: Build UI
+description: Restore cached UI HTML artifacts, or set up Node and run script/build-ui on cache miss.
+
+runs:
+  using: composite
+  steps:
+    - name: Cache UI artifacts
+      id: cache-ui
+      uses: actions/cache@v5
+      with:
+        path: |
+          pkg/github/ui_dist/get-me.html
+          pkg/github/ui_dist/issue-write.html
+          pkg/github/ui_dist/pr-write.html
+        key: ui-dist-v1-${{ hashFiles('ui/package-lock.json', 'ui/package.json', 'ui/index.html', 'ui/tsconfig*.json', 'ui/vite.config.ts', 'ui/src/**', 'ui/scripts/**') }}
+        enableCrossOsArchive: true
+
+    - name: Set up Node.js
+      if: steps.cache-ui.outputs.cache-hit != 'true'
+      uses: actions/setup-node@v6
+      with:
+        node-version: "20"
+        cache: npm
+        cache-dependency-path: ui/package-lock.json
+
+    - name: Build UI
+      if: steps.cache-ui.outputs.cache-hit != 'true'
+      shell: bash
+      run: script/build-ui
+
+    - name: Report UI cache status
+      shell: bash
+      run: |
+        if [ "${{ steps.cache-ui.outputs.cache-hit }}" = "true" ]; then
+          echo "UI artifacts restored from cache (skipped build)."
+        else
+          echo "UI artifacts rebuilt from source."
+        fi

.github/workflows/code-scanning.yml

@@ -78,8 +78,8 @@ jobs:
           go-version: ${{ fromJSON(steps.resolve-environment.outputs.environment).configuration.go.version }}
           cache: false
 
-      - name: Set up Node.js
-        if: matrix.language == 'go' || matrix.language == 'javascript'
+      - name: Set up Node.js (for JavaScript CodeQL)
+        if: matrix.language == 'javascript'
         uses: actions/setup-node@v6
         with:
           node-version: "20"
@@ -88,7 +88,7 @@ jobs:
 
       - name: Build UI
         if: matrix.language == 'go'
-        run: script/build-ui
+        uses: ./.github/actions/build-ui
 
       - name: Autobuild
         uses: github/codeql-action/autobuild@v4

.github/workflows/docs-check.yml

@@ -16,15 +16,8 @@ jobs:
     - name: Checkout code
       uses: actions/checkout@v6
 
-    - name: Set up Node.js
-      uses: actions/setup-node@v6
-      with:
-        node-version: "20"
-        cache: "npm"
-        cache-dependency-path: ui/package-lock.json
-
     - name: Build UI
-      run: script/build-ui
+      uses: ./.github/actions/build-ui
 
     - name: Set up Go
       uses: actions/setup-go@v6

.github/workflows/go.yml

@@ -25,16 +25,8 @@ jobs:
       - name: Check out code
         uses: actions/checkout@v6
 
-      - name: Set up Node.js
-        uses: actions/setup-node@v6
-        with:
-          node-version: "20"
-          cache: "npm"
-          cache-dependency-path: ui/package-lock.json
-
       - name: Build UI
-        shell: bash
-        run: script/build-ui
+        uses: ./.github/actions/build-ui
 
       - name: Set up Go
         uses: actions/setup-go@v6

.github/workflows/goreleaser.yml

@@ -16,15 +16,8 @@ jobs:
       - name: Check out code
         uses: actions/checkout@v6
 
-      - name: Set up Node.js
-        uses: actions/setup-node@v6
-        with:
-          node-version: "20"
-          cache: "npm"
-          cache-dependency-path: ui/package-lock.json
-
       - name: Build UI
-        run: script/build-ui
+        uses: ./.github/actions/build-ui
 
       - name: Set up Go
         uses: actions/setup-go@v6

.github/workflows/license-check.yml

@@ -32,15 +32,8 @@ jobs:
           GH_TOKEN: ${{ github.token }}
         run: gh pr checkout ${{ github.event.pull_request.number }}
 
-      - name: Set up Node.js
-        uses: actions/setup-node@v6
-        with:
-          node-version: "20"
-          cache: "npm"
-          cache-dependency-path: ui/package-lock.json
-
       - name: Build UI
-        run: script/build-ui
+        uses: ./.github/actions/build-ui
 
       - name: Set up Go
         uses: actions/setup-go@v6

.github/workflows/lint.yml

@@ -14,13 +14,8 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v6
-      - uses: actions/setup-node@v6
-        with:
-          node-version: "20"
-          cache: "npm"
-          cache-dependency-path: ui/package-lock.json
       - name: Build UI
-        run: script/build-ui
+        uses: ./.github/actions/build-ui
       - uses: actions/setup-go@v6
         with:
           go-version: '1.25'

.github/workflows/mcp-diff.yml

@@ -19,13 +19,8 @@ jobs:
         with:
           fetch-depth: 0
 
-      - name: Set up Node.js
-        uses: actions/setup-node@v6
-        with:
-          node-version: '20'
-
       - name: Build UI
-        run: script/build-ui
+        uses: ./.github/actions/build-ui
 
       - name: Run MCP Server Diff
         uses: SamMorrowDrums/mcp-server-diff@v2.3.5