fix(ci): run throughput bench in its own walltime job

CodSpeed walltime mode finalizes result collection once per process, so a second withCodSpeed bench.run() in the same process has no latency to collect and crashes (TypeError destructuring result.latency). walltime.ts combined startup + throughput in one process; split throughput into its own job so each walltime process runs a single bench.

Author: natemoo-re

.github/workflows/benchmark.yml

@@ -136,8 +136,52 @@ jobs:
         if: steps.deno-cache.outputs.cache-hit != 'true'
         run: deno install
 
-      - name: Run walltime benchmarks
+      - name: Run startup benchmarks
         uses: CodSpeedHQ/action@9d332c4d90b43981c3e55ae8e38e68709996240f # v4.17.0
         with:
           mode: walltime
-          run: node bench/walltime.ts
+          run: node bench/startup.bench.ts
+
+  throughput:
+    name: Run benchmarks (throughput)
+    needs: build
+    runs-on: codspeed-macro
+    permissions:
+      contents: read # clone repo
+      id-token: write # upload benchmark results to codspeed
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6.0.3
+
+      - name: Setup Deno
+        uses: denoland/setup-deno@667a34cdef165d8d2b2e98dde39547c9daac7282 # v2.0.4
+        with:
+          deno-version: v2.x
+
+      - name: Setup Node
+        uses: actions/setup-node@48b55a011bda9f5d6aeb4c2d9c7362e8dae4041e # v6.4.0
+        with:
+          node-version: 24
+
+      - name: Download build artifact
+        uses: actions/download-artifact@3e5f45b2cfb9172054b4087a40e8e0b5a5461e7c # v8.0.1
+        with:
+          name: bench-build
+
+      - name: Restore dependencies
+        uses: actions/cache@27d5ce7f107fe9357f9df03efb73ab90386fccae # v5.0.5
+        id: deno-cache
+        with:
+          path: node_modules
+          key: deno-codspeed-${{ runner.arch }}-${{ hashFiles('deno.lock') }}
+
+      - name: Install dependencies
+        if: steps.deno-cache.outputs.cache-hit != 'true'
+        run: deno install
+
+      - name: Run throughput benchmark
+        uses: CodSpeedHQ/action@9d332c4d90b43981c3e55ae8e38e68709996240f # v4.17.0
+        with:
+          mode: walltime
+          run: node bench/throughput.bench.ts