diff --git a/.github/actions/install-node-dependencies/action.yml b/.github/actions/install-node-dependencies/action.yml
index 73fbf9d320c..f65a9dcfd99 100644
--- a/.github/actions/install-node-dependencies/action.yml
+++ b/.github/actions/install-node-dependencies/action.yml
@@ -2,10 +2,10 @@ name: Install Node dependencies
 description: Installs the Node toolchain and repository dependencies for Linux CI jobs.
 
 inputs:
-  ignore-scripts:
-    description: Skip dependency lifecycle scripts when the job does not need native runtimes.
+  native-runtime:
+    description: Native runtime to prepare after the script-free install (none, node, or electron).
     required: false
-    default: 'false'
+    default: none
 
 runs:
   using: composite
@@ -22,9 +22,22 @@ runs:
         node-version-file: package.json
         cache: pnpm
 
+    - name: Validate native runtime
+      shell: bash
+      env:
+        NATIVE_RUNTIME: ${{ inputs.native-runtime }}
+      run: |
+        case "$NATIVE_RUNTIME" in
+          none|node|electron) ;;
+          *)
+            echo "::error::native-runtime must be none, node, or electron"
+            exit 2
+            ;;
+        esac
+
     # pnpm's bundled gyp_main.py is not executable on fresh Linux runners.
     - name: Use external node-gyp
-      if: inputs.ignore-scripts != 'true'
+      if: inputs.native-runtime != 'none'
       shell: bash
       run: |
         npm install -g node-gyp@11.5.0
@@ -40,15 +53,19 @@ runs:
 
     - name: Install dependencies
       shell: bash
-      env:
-        IGNORE_SCRIPTS: ${{ inputs.ignore-scripts }}
       run: |
-        install_args=(--no-frozen-lockfile --prefer-frozen-lockfile=false --os=current --os=win32 --cpu=current)
-        if [ "$IGNORE_SCRIPTS" = "true" ]; then
-          install_args+=(--ignore-scripts)
-        elif [ "$IGNORE_SCRIPTS" != "false" ]; then
-          echo "::error::ignore-scripts must be true or false"
-          exit 2
-        fi
-        pnpm install "${install_args[@]}"
+        pnpm install \
+          --no-frozen-lockfile \
+          --prefer-frozen-lockfile=false \
+          --os=current \
+          --os=win32 \
+          --cpu=current \
+          --ignore-scripts
         git diff --exit-code package.json pnpm-lock.yaml
+
+    - name: Prepare native runtime
+      if: inputs.native-runtime != 'none'
+      shell: bash
+      env:
+        NATIVE_RUNTIME: ${{ inputs.native-runtime }}
+      run: node config/scripts/ensure-native-runtime.mjs --runtime="$NATIVE_RUNTIME"
diff --git a/.github/workflows/pr.yml b/.github/workflows/pr.yml
index 9ea0ab19477..183339d2918 100644
--- a/.github/workflows/pr.yml
+++ b/.github/workflows/pr.yml
@@ -24,8 +24,6 @@ jobs:
           persist-credentials: false
 
       - uses: ./.github/actions/install-node-dependencies
-        with:
-          ignore-scripts: 'true'
 
       - name: Lint
         run: pnpm exec oxlint --format github
@@ -73,8 +71,6 @@ jobs:
           persist-credentials: false
 
       - uses: ./.github/actions/install-node-dependencies
-        with:
-          ignore-scripts: 'true'
 
       - run: pnpm typecheck
 
@@ -89,8 +85,6 @@ jobs:
           persist-credentials: false
 
       - uses: ./.github/actions/install-node-dependencies
-        with:
-          ignore-scripts: 'true'
 
       - name: Verify Git binary compatibility matrix
         run: |
@@ -144,10 +138,11 @@ jobs:
         run: sudo apt-get update && sudo apt-get install -y zsh
 
       - uses: ./.github/actions/install-node-dependencies
+        with:
+          native-runtime: node
 
       - name: Test real shell contracts
         run: |
-          node config/scripts/ensure-native-runtime.mjs --runtime=node
           pnpm exec vitest run --config config/vitest.config.ts \
             src/main/daemon/shell-ready.test.ts \
             src/main/daemon/node-pty-fd-leak.test.ts \
@@ -172,7 +167,7 @@ jobs:
 
       - uses: ./.github/actions/install-node-dependencies
         with:
-          ignore-scripts: 'true'
+          native-runtime: node
 
       - name: Install Electron package binary for tests
         run: node config/scripts/install-electron-package-binary.mjs
@@ -198,10 +193,6 @@ jobs:
         with:
           persist-credentials: false
 
-      - uses: ./.github/actions/install-node-dependencies
-        with:
-          ignore-scripts: 'true'
-
       - name: Cache electron-builder downloads
         uses: actions/cache@v5
         with:
@@ -212,16 +203,17 @@ jobs:
           restore-keys: |
             electron-builder-linux-
 
-      # Native preparation does not touch the bundle output directories.
+      - uses: ./.github/actions/install-node-dependencies
+        with:
+          native-runtime: electron
+
       - name: Build package inputs
         run: |
-          pnpm run ensure:electron-runtime &
-          pids=("$!")
-
           status=0
           pnpm run build:cli || status=1
 
           scripts=(build:relay build:electron-vite:parallel)
+          pids=()
           for script in "${scripts[@]}"; do
             pnpm run "$script" &
             pids+=("$!")
diff --git a/config/scripts/electron-vite-output-contract.test.ts b/config/scripts/electron-vite-output-contract.test.ts
index 6e0a356b167..3347e36cf50 100644
--- a/config/scripts/electron-vite-output-contract.test.ts
+++ b/config/scripts/electron-vite-output-contract.test.ts
@@ -26,4 +26,10 @@ describe('Electron Vite output contract', () => {
     expect(external('@xterm/headless', undefined, false)).toBe(false)
     expect(external('@xterm/addon-serialize', undefined, false)).toBe(false)
   })
+
+  it('isolates renderer entry side effects behind strict facades', () => {
+    expect(electronViteConfig.renderer?.build?.rollupOptions?.preserveEntrySignatures).toBe(
+      'strict'
+    )
+  })
 })
diff --git a/config/scripts/pr-workflow-parallelism.test.mjs b/config/scripts/pr-workflow-parallelism.test.mjs
index 08d60969a07..1bbfc44d2e7 100644
--- a/config/scripts/pr-workflow-parallelism.test.mjs
+++ b/config/scripts/pr-workflow-parallelism.test.mjs
@@ -49,15 +49,18 @@ describe('PR workflow parallelism', () => {
     const shellStep = workflow.jobs.shell_contracts.steps.find(
       (step) => step.name === 'Test real shell contracts'
     )
+    const shellInstall = workflow.jobs.shell_contracts.steps.find(
+      (step) => step.uses === './.github/actions/install-node-dependencies'
+    )
 
     expect(workflow.jobs.test.steps.some((step) => step.name === 'Install zsh')).toBe(false)
     expect(workflow.jobs.shell_contracts.steps.some((step) => step.name === 'Install zsh')).toBe(
       true
     )
+    expect(shellInstall.with['native-runtime']).toBe('node')
     for (const testFile of nativeShellContractFiles) {
       expect(shellStep.run).toContain(testFile)
     }
-    expect(shellStep.run).toContain('ensure-native-runtime.mjs --runtime=node')
   })
 
   it('keeps every real-zsh test in the dedicated shell lane', () => {
@@ -74,7 +77,6 @@ describe('PR workflow parallelism', () => {
     )
 
     expect(buildStep.run).toContain('scripts=(build:relay build:electron-vite:parallel)')
-    expect(buildStep.run).toContain('pnpm run ensure:electron-runtime &')
     expect(buildStep.run).toContain('pnpm run "$script" &')
     expect(
       workflow.jobs.package.steps.find(
@@ -94,41 +96,45 @@ describe('PR workflow parallelism', () => {
     expect(steps[nodeIndex].with.cache).toBe('pnpm')
   })
 
-  it('skips lifecycle scripts outside native-runtime test setup', () => {
-    for (const jobName of [
-      'static_analysis',
-      'typecheck',
-      'git_compatibility',
-      'test',
-      'package'
-    ]) {
-      const installStep = workflow.jobs[jobName].steps.find(
-        (step) => step.uses === './.github/actions/install-node-dependencies'
-      )
-      expect(installStep.with['ignore-scripts'], jobName).toBe('true')
-    }
-
-    const shellInstall = workflow.jobs.shell_contracts.steps.find(
+  it('restores Electron downloads before preparing the package runtime', () => {
+    const steps = workflow.jobs.package.steps
+    const cacheIndex = steps.findIndex((step) => step.name === 'Cache electron-builder downloads')
+    const installIndex = steps.findIndex(
       (step) => step.uses === './.github/actions/install-node-dependencies'
     )
-    expect(shellInstall.with).toBeUndefined()
+
+    expect(cacheIndex).toBeLessThan(installIndex)
+  })
+
+  it('prepares each native runtime before its consumers start', () => {
+    const installFor = (jobName) =>
+      workflow.jobs[jobName].steps.find(
+        (step) => step.uses === './.github/actions/install-node-dependencies'
+      )
+
+    for (const jobName of ['static_analysis', 'typecheck', 'git_compatibility']) {
+      expect(installFor(jobName).with, jobName).toBeUndefined()
+    }
+    expect(installFor('shell_contracts').with['native-runtime']).toBe('node')
+    expect(installFor('test').with['native-runtime']).toBe('node')
+    expect(installFor('package').with['native-runtime']).toBe('electron')
+
     expect(
       dependencyAction.runs.steps.find((step) => step.name === 'Use external node-gyp').if
-    ).toBe("inputs.ignore-scripts != 'true'")
+    ).toBe("inputs.native-runtime != 'none'")
     const dependencyInstall = dependencyAction.runs.steps.find(
       (step) => step.name === 'Install dependencies'
     )
-    expect(dependencyInstall.env.IGNORE_SCRIPTS).toBe('${{ inputs.ignore-scripts }}')
-    expect(dependencyInstall.run).toContain(
-      '--no-frozen-lockfile --prefer-frozen-lockfile=false --os=current --os=win32 --cpu=current'
-    )
-    expect(dependencyInstall.run).toContain('install_args+=(--ignore-scripts)')
-    expect(workflow.jobs.test.steps.find((step) => step.name === 'Test shard').run).not.toContain(
-      'ensure-native-runtime'
+    expect(dependencyInstall.run).toContain('--no-frozen-lockfile')
+    expect(dependencyInstall.run).toContain('--ignore-scripts')
+    const prepareRuntime = dependencyAction.runs.steps.find(
+      (step) => step.name === 'Prepare native runtime'
     )
+    expect(prepareRuntime.if).toBe("inputs.native-runtime != 'none'")
+    expect(prepareRuntime.run).toContain('ensure-native-runtime.mjs --runtime="$NATIVE_RUNTIME"')
   })
 
-  it('reuses native preparation only after the concurrent runtime gate', () => {
+  it('reuses native preparation after the dependency action gate', () => {
     const buildStep = workflow.jobs.package.steps.find(
       (step) => step.name === 'Build package inputs'
     )
@@ -136,7 +142,7 @@ describe('PR workflow parallelism', () => {
       (step) => step.name === 'Package unpacked app'
     )
 
-    expect(buildStep.run).toContain('pnpm run ensure:electron-runtime &')
+    expect(buildStep.run).not.toContain('ensure:electron-runtime')
     expect(packageStep.env.ORCA_REUSE_PREPARED_NATIVE_RUNTIME).toBe('1')
   })
 
diff --git a/config/scripts/project-renderer-web-client.mjs b/config/scripts/project-renderer-web-client.mjs
index 6aba500330a..77516332523 100644
--- a/config/scripts/project-renderer-web-client.mjs
+++ b/config/scripts/project-renderer-web-client.mjs
@@ -19,6 +19,36 @@ const manifest = JSON.parse(readFileSync(manifestPath, 'utf8'))
 const selectedFiles = new Set(['web-index.html'])
 const visitedEntries = new Set()
 
+function assertEntryIsolation() {
+  const entryKeys = new Set(
+    Object.entries(manifest)
+      .filter(([, entry]) => entry?.isEntry === true)
+      .map(([key]) => key)
+  )
+
+  for (const sourceEntry of entryKeys) {
+    const visited = new Set()
+    const pending = [sourceEntry]
+    while (pending.length > 0) {
+      const key = pending.pop()
+      if (visited.has(key)) {
+        continue
+      }
+      visited.add(key)
+      const entry = manifest[key]
+      if (!entry || typeof entry !== 'object') {
+        throw new Error(`Renderer manifest is missing entry: ${key}`)
+      }
+      for (const dependency of [...(entry.imports ?? []), ...(entry.dynamicImports ?? [])]) {
+        if (entryKeys.has(dependency) && dependency !== sourceEntry) {
+          throw new Error(`Renderer entry ${sourceEntry} executes entry ${dependency}`)
+        }
+        pending.push(dependency)
+      }
+    }
+  }
+}
+
 function addOutputPath(outputPath) {
   if (
     typeof outputPath !== 'string' ||
@@ -107,6 +137,7 @@ async function minifyWebOutput() {
   )
 }
 
+assertEntryIsolation()
 visitManifestEntry('web-index.html')
 includeReferencedOutputs()
 
diff --git a/config/scripts/project-renderer-web-client.test.mjs b/config/scripts/project-renderer-web-client.test.mjs
index 44f109ca9b9..49bc0da7c5e 100644
--- a/config/scripts/project-renderer-web-client.test.mjs
+++ b/config/scripts/project-renderer-web-client.test.mjs
@@ -98,4 +98,20 @@ describe('renderer web client projection', () => {
     expect(result.status).toBe(1)
     expect(result.stderr).toContain('Renderer manifest is missing entry: web-index.html')
   })
+
+  it('rejects renderer entries that execute another entry root', () => {
+    const root = createRendererFixture()
+    const manifestPath = join(root, 'out/renderer/.vite/manifest.json')
+    const manifest = JSON.parse(readFileSync(manifestPath, 'utf8'))
+    manifest['web-index.html'].dynamicImports.push('index.html')
+    writeFileSync(manifestPath, JSON.stringify(manifest))
+
+    const result = spawnSync(process.execPath, [scriptPath], {
+      cwd: root,
+      encoding: 'utf8'
+    })
+
+    expect(result.status).toBe(1)
+    expect(result.stderr).toContain('Renderer entry web-index.html executes entry index.html')
+  })
 })
diff --git a/electron.vite.config.ts b/electron.vite.config.ts
index fa9205ac920..d5fb6ebd1dc 100644
--- a/electron.vite.config.ts
+++ b/electron.vite.config.ts
@@ -277,6 +277,9 @@ export const electronViteConfig: UserConfig = {
       // stay listed — overriding input otherwise drops electron-vite's default
       // renderer entry.
       rollupOptions: {
+        // Why: shared chunks must never import an HTML entry whose module mounts
+        // a different React root.
+        preserveEntrySignatures: 'strict',
         input: {
           index: resolve('src/renderer/index.html'),
           popout: resolve('src/renderer/popout.html'),