A-g: run the quick free tier on GSTACK_BUN_DEFAULT in CI; drift test pins it

Co-authored-by: capy-ai[bot] <230910855+capy-ai[bot]@users.noreply.github.com>

.github/workflows/free-tests.yml

@@ -227,6 +227,57 @@ jobs:
       - name: CSO source formatting
         run: bun run format:cso:check
 
+  # Capy machines install GSTACK_BUN_DEFAULT (bin/gstack-bun-version.sh) when
+  # no project pin decides, above the 1.4.2 minimum every other lane pins, so
+  # the quick tier also runs on it. Its pin equals GSTACK_BUN_DEFAULT;
+  # test/bun-version-drift.test.ts checks this job exists and agrees.
+  quick-bun-default:
+    runs-on: ubuntu-24.04
+    timeout-minutes: 30
+    steps:
+      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7
+        with:
+          persist-credentials: false
+      - uses: oven-sh/setup-bun@0c5077e51419868618aeaa5fe8019c62421857d6 # v2
+        with:
+          bun-version: 1.4.3
+      - name: Install dependencies
+        run: bun install --frozen-lockfile
+      - name: Install Playwright Chromium
+        run: npx playwright install --with-deps chromium
+      - name: Configure the bundled Chromium sandbox helper
+        run: |
+          set -euo pipefail
+          chrome=$(bun -e 'import { chromium } from "playwright"; import { realpathSync } from "node:fs"; console.log(realpathSync(chromium.executablePath()))')
+          case "$chrome" in
+            "$HOME"/.cache/ms-playwright/chromium-*/chrome-linux*/chrome) ;;
+            *) echo "Unexpected Chromium installation path" >&2; exit 1 ;;
+          esac
+          helper="${chrome%/*}/chrome_sandbox"
+          installed="${chrome%/*}/chrome-sandbox"
+          test -f "$helper" && test ! -L "$helper"
+          sudo install -T -o root -g root -m 4755 "$helper" "$installed"
+      - name: Install Xvfb + X11 utilities + gate tools
+        run: sudo apt-get install -y --no-install-recommends xvfb x11-utils poppler-utils fonts-noto-color-emoji zsh
+      - name: Configure git identity (tests init temp repos)
+        run: |
+          git config --global user.email "free-tests-ci@gstack.test"
+          git config --global user.name "Free Tests CI"
+          git config --global init.defaultBranch main
+          git config --global --add safe.directory '*'
+      - name: Generate host SKILL.md outputs (.agents, .factory)
+        run: bun run gen:skill-docs --host all
+      - name: Vendor xterm assets into the extension
+        run: bun run vendor:xterm
+      - name: Build server-node bundle (loaded by browse cli imports)
+        run: bash browse/scripts/build-node-server.sh
+      - name: Build gate binaries (make-pdf e2e gates)
+        run: bun run build:gates
+      - name: Build trusted CSO helper used by free contract tests
+        run: bun run build:cso
+      - name: Run the quick free tier on the install-default Bun
+        run: xvfb-run -a bun run test:quick
+
   free-suite:
     needs: free-plan
     runs-on: ubicloud-standard-8
@@ -396,14 +447,15 @@ jobs:
   # gate is merge-blocking without a separate branch-protection migration.
   free-tests:
     if: always()
-    needs: [free-suite, typecheck, cso-macos-launcher, macos-named-regressions, cso-windows-launcher, cso-docker-integration]
+    needs: [free-suite, typecheck, quick-bun-default, cso-macos-launcher, macos-named-regressions, cso-windows-launcher, cso-docker-integration]
     runs-on: ubuntu-24.04
     timeout-minutes: 5
     steps:
-      - name: Require the free suite, typecheck, macOS regressions, and every CSO platform gate
+      - name: Require the free suite, typecheck, the quick tier on the default Bun, macOS regressions, and every CSO platform gate
         env:
           FREE_SUITE_RESULT: ${{ needs.free-suite.result }}
           TYPECHECK_RESULT: ${{ needs.typecheck.result }}
+          QUICK_BUN_DEFAULT_RESULT: ${{ needs.quick-bun-default.result }}
           CSO_MACOS_RESULT: ${{ needs.cso-macos-launcher.result }}
           MACOS_REGRESSIONS_RESULT: ${{ needs.macos-named-regressions.result }}
           CSO_WINDOWS_RESULT: ${{ needs.cso-windows-launcher.result }}
@@ -412,6 +464,7 @@ jobs:
           set -eu
           test "$FREE_SUITE_RESULT" = success
           test "$TYPECHECK_RESULT" = success
+          test "$QUICK_BUN_DEFAULT_RESULT" = success
           test "$CSO_MACOS_RESULT" = success
           test "$MACOS_REGRESSIONS_RESULT" = success
           test "$CSO_WINDOWS_RESULT" = success