Stabilize release preflight scheduling

docs/release-control/v6/internal/subsystems/deployment-installability.md

@@ -42,6 +42,14 @@ upgrade must recover those values from both split and `--key=value` service
 arguments and reproduce them in the generated systemd command without
 discarding existing explicit disk exclusions.
 
+The accelerated exact-SHA release worker must preserve release-gate fidelity
+under its own resource envelope. Bounded frontend static checks and integration
+image preparation may overlap, but the full frontend test suite and the
+race-enabled backend release suite must run serially. Both suites saturate the
+dedicated worker when combined; concurrent execution can stretch otherwise
+passing monitoring tests into load-induced failures and must not be used as a
+release-latency optimization.
+
 ## Canonical Files
 
 1. `internal/updates/`

scripts/release-preflight-worker.sh

@@ -135,11 +135,14 @@ phase frontend-build npm --prefix frontend-modern run build
 rm -rf internal/api/frontend-modern
 mkdir -p internal/api/frontend-modern
 cp -R frontend-modern/dist internal/api/frontend-modern/
-run_frontend_quality() {
+run_frontend_static_quality() {
   phase frontend-lint npm --prefix frontend-modern run lint
   phase frontend-headers npm --prefix frontend-modern run lint:headers
   phase frontend-duplication npm --prefix frontend-modern run lint:cpd
   phase frontend-types npm --prefix frontend-modern run type-check
+}
+
+run_frontend_tests() {
   phase frontend-tests npm --prefix frontend-modern test
 }
 
@@ -163,12 +166,12 @@ run_integration_prep() {
   phase mock-github-image docker build --tag pulse-mock-github:test tests/integration/mock-github-server
 }
 
-# These lanes have no output dependency on one another. Running them together
-# makes the critical path the slowest lane instead of their sum.
+# Static frontend checks and integration preparation are bounded enough to
+# overlap safely. Keep the full frontend and race-enabled backend test suites
+# serial: both saturate this worker, and concurrent execution can turn healthy
+# monitoring tests into load-induced release-gate failures.
 parallel_pids=()
-run_frontend_quality &
-parallel_pids+=("$!")
-run_backend &
+run_frontend_static_quality &
 parallel_pids+=("$!")
 run_integration_prep &
 parallel_pids+=("$!")
@@ -185,6 +188,9 @@ while [ "$remaining" -gt 0 ]; do
   fi
 done
 
+run_frontend_tests
+run_backend
+
 PLAYWRIGHT_VERSION="$(node -p "require('./tests/integration/node_modules/@playwright/test/package.json').version")"
 PLAYWRIGHT_IMAGE="mcr.microsoft.com/playwright:v${PLAYWRIGHT_VERSION}-noble"
 

scripts/release_control/internal/release_preflight_test.py

@@ -217,6 +217,23 @@ class ReleasePreflightTest(unittest.TestCase):
         )
         self.assertIn("is not reachable from a fetched origin branch", runner)
 
+    def test_worker_serializes_resource_intensive_test_suites(self) -> None:
+        worker = (ROOT / "scripts/release-preflight-worker.sh").read_text()
+        scheduling_block = re.search(
+            r"# Static frontend checks.*?run_backend\n",
+            worker,
+            flags=re.DOTALL,
+        )
+        self.assertIsNotNone(scheduling_block)
+        block = scheduling_block.group(0)
+
+        self.assertIn("run_frontend_static_quality &", block)
+        self.assertIn("run_integration_prep &", block)
+        self.assertNotIn("run_frontend_tests &", block)
+        self.assertNotIn("run_backend &", block)
+        self.assertLess(block.index("done\n"), block.index("run_frontend_tests\n"))
+        self.assertLess(block.index("run_frontend_tests\n"), block.index("run_backend\n"))
+
     def test_api_shard_plan_is_deterministic_complete_and_disjoint(self) -> None:
         test_names = [
             f"TestReleaseCase{index:04d}"