Rewrite explorer in vanilla JS + Bootstrap 5.3.8

.github/workflows/pages.yml

@@ -0,0 +1,56 @@
+name: Deploy to GitHub Pages
+
+# The new (post-rewrite) site has no build step. The repo carries
+# index.html and src/ directly, plus a pre-built CodeMirror bundle in
+# src/vendor/. Deployment is just "stage those files and upload them" —
+# no Node setup, no npm install, no bundler.
+
+on:
+  push:
+    branches: [ "main" ]
+  workflow_dispatch:
+
+permissions:
+  contents: read
+  pages: write
+  id-token: write
+
+# One deploy at a time, queued. Don't cancel an in-flight deploy because
+# we want production runs to complete.
+concurrency:
+  group: "pages"
+  cancel-in-progress: false
+
+jobs:
+  deploy:
+    environment:
+      name: github-pages
+      url: ${{ steps.deployment.outputs.page_url }}
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      # Stage only the files that should be publicly served. Excludes
+      # package.json, scripts/, test/, planning docs, mockup.html, etc.
+      #
+      # IMPORTANT: `src/` is the deploy boundary. Anything committed under
+      # that path is published to GitHub Pages on the next main-branch
+      # push. Do not commit secrets, scratch queries, fixtures, or local
+      # mocks to `src/`. If you need a file that shouldn't ship, put it
+      # somewhere else (e.g. `scripts/`, `test/`, or a tracked-but-ignored
+      # path outside `src/`).
+      - name: Stage site
+        run: |
+          mkdir _site
+          cp index.html _site/
+          cp -r src _site/
+
+      - name: Upload artifact
+        uses: actions/upload-pages-artifact@v3
+        with:
+          path: _site
+
+      - name: Deploy to GitHub Pages
+        id: deployment
+        uses: actions/deploy-pages@v4

.github/workflows/test.yml

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+name: Test
+
+# Runs the node:test suite on every push to main/develop and on every
+# pull request. The suite has zero dependencies (node:test is built into
+# Node 20), so there is no `npm install` step — checkout, set up Node,
+# run the tests.
+
+on:
+  push:
+    branches: [ "main", "develop" ]
+  pull_request:
+
+# One test run at a time per ref. Rapid pushes to the same PR branch
+# cancel the previous in-flight run so we only pay for the latest commit.
+concurrency:
+  group: test-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Setup Node
+        uses: actions/setup-node@v4
+        with:
+          node-version: "20"
+
+      - name: Run tests
+        run: npm test