ci: add temporary PATH probe job to diagnose memory-mode flag loss

Generated with AI Agent (Claude Code)

Author: GuillaumeLagrange

.github/workflows/codspeed.yml

@@ -7,6 +7,41 @@ on:
   workflow_dispatch:
 
 jobs:
+  # TEMPORARY diagnostic — remove before merge.
+  # Proves whether turbo/pnpm demotes the runner's introspected-node PATH shim
+  # in memory mode. Compares node resolution & flags: (a) directly, (b) through
+  # `pnpm turbo run`, (c) through `pnpm --filter run`.
+  path-probe:
+    name: PATH probe (memory mode)
+    runs-on: "ubuntu-latest"
+    steps:
+      - uses: "actions/checkout@v4"
+        with:
+          fetch-depth: 0
+          submodules: true
+      - uses: pnpm/action-setup@v2
+      - uses: actions/setup-node@v3
+        with:
+          cache: pnpm
+          node-version-file: .nvmrc
+      - run: pnpm install --frozen-lockfile --prefer-offline
+      - run: pnpm turbo run build
+
+      - name: Probe under memory mode
+        uses: CodSpeedHQ/action@main
+        with:
+          mode: memory
+          run: |
+            PROBE='console.log("execPath="+process.execPath); console.log("execArgv="+JSON.stringify(process.execArgv)); console.log("PATHhead="+(process.env.PATH||"").split(":").slice(0,3).join(":")); try { eval("%OptimizeFunctionOnNextCall(()=>{})"); console.log("natives=OK") } catch(e){ console.log("natives=FAIL "+e.message) }'
+            echo "=== (a) direct node (runner PATH intact) ==="
+            echo "PATHhead(shell)=$(echo $PATH | cut -d: -f1-3)"
+            echo "which node=$(command -v node)"
+            node -e "$PROBE"
+            echo "=== (b) via pnpm exec node (pnpm PATH reconstruction, same family as turbo) ==="
+            pnpm exec node -e "$PROBE" || echo "pnpm exec exit=$?"
+            echo "=== (c) via pnpm turbo run bench (real path, expect FAIL) ==="
+            pnpm turbo run bench --filter=@codspeed/tinybench-plugin 2>&1 | grep -iE "execPath|natives|missing required|SyntaxError|Measured" || true
+
   codspeed-instrumented:
     name: Run CodSpeed instrumented (${{ matrix.plugin }})
     runs-on: "ubuntu-latest"