feat: add endpoint-isolated common warm-up screening

.github/workflows/common-warmup-screen.yml

@@ -0,0 +1,41 @@
+name: Common warm-up screen v1
+on:
+  workflow_dispatch:
+permissions:
+  contents: read
+concurrency:
+  group: common-warmup-screen
+  cancel-in-progress: false
+jobs:
+  screen:
+    if: >-
+      github.repository == 'tappe9/simple-api-benchmark' &&
+      github.ref == format('refs/heads/{0}', github.event.repository.default_branch) &&
+      github.event_name == 'workflow_dispatch'
+    runs-on: ubuntu-24.04
+    timeout-minutes: 120
+    env:
+      PYTHONDONTWRITEBYTECODE: '1'
+    steps:
+      - uses: actions/checkout@fbc6f3992d24b796d5a048ff273f7fcc4a7b6c09
+        timeout-minutes: 3
+        with:
+          ref: ${{ github.sha }}
+          fetch-depth: 1
+          persist-credentials: false
+      - uses: actions/setup-python@a26af69be951a213d495a4c3e4e4022e16d87065
+        timeout-minutes: 3
+        with:
+          python-version-file: apps/python-fastapi/.python-version
+      - name: Run one fixed endpoint-isolated screen, reserving cleanup and upload time
+        run: timeout --signal=TERM --kill-after=120s 104m python -m benchmark.common_warmup_screen
+      - name: Retain complete common warm-up screen evidence, including failures
+        if: always()
+        uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02
+        timeout-minutes: 7
+        with:
+          name: common-warmup-screen-${{ github.run_id }}-${{ github.run_attempt }}
+          path: .cache/common-warmup-screen/
+          include-hidden-files: true
+          retention-days: 90
+          if-no-files-found: error