Add: preview_pages用のWorkflowを追加

.github/workflows/DANGEROUS_trigger_preview_pages.yml

@@ -0,0 +1,26 @@
+name: "Trigger preview-pages' workflow"
+
+# プレビュー用ページのワークフローを起動する。
+# 詳細： https://github.com/voicevox/preview-pages?tab=readme-ov-file#%E4%BB%95%E7%B5%84%E3%81%BF
+
+on:
+  pull_request_target:
+    types:
+      - opened
+      - synchronize
+      - closed
+      - reopened
+  push:
+    branches:
+      - main
+      - project-*
+
+jobs:
+  trigger:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Trigger Workflow
+        run: |
+          gh workflow run -R voicevox/preview-pages update_pages.yml
+        env:
+          GH_TOKEN: ${{ secrets.TRIGGER_PREVIEW_PAGES_TOKEN }}

.github/workflows/build_preview_pages.yml

@@ -0,0 +1,32 @@
+name: "Build Preview Pages"
+
+# プレビュー用ページをビルドする。
+# 詳細： https://github.com/voicevox/preview-pages?tab=readme-ov-file#%E4%BB%95%E7%B5%84%E3%81%BF
+
+on:
+  push:
+    branches:
+      - main
+      - project-*
+  pull_request:
+
+jobs:
+  update_pages:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Setup environment
+        uses: ./.github/actions/setup-environment
+
+      - name: Build
+        run: |
+          npm run storybook:build -- --preview-url ./ --output-dir dist_preview/storybook
+          npm run browser:build -- --base ./ --outDir dist_preview/editor
+
+      - name: Upload artifact
+        uses: actions/upload-artifact@v4
+        with:
+          name: preview-pages
+          path: dist_preview

.gitignore

@@ -44,3 +44,6 @@ electron-builder.yml
 
 # Storybook
 storybook-static/
+
+# Preview Build Output
+dist_preview/

src/backend/browser/sandbox.ts

@@ -20,7 +20,8 @@ import {
 import { AssetTextFileNames } from "@/type/staticResources";
 
 // TODO: base pathを設定できるようにするか、ビルド時埋め込みにする
-const toStaticPath = (fileName: string) => `/${fileName}`;
+const toStaticPath = (fileName: string) =>
+  `${import.meta.env.BASE_URL}/${fileName}`.replaceAll(/\/\/+/, "/");
 
 // FIXME: asを使わないようオーバーロードにした。オーバーロードも使わない書き方にしたい。
 function onReceivedIPCMsg<