Restore pull_request_review trigger for benchmark workflow

PR #1124 changed bench.yml to use workflow_run (triggered after Test
Suite completes), which broke the approve-to-run flow for fork PRs.
Revert to the original pull_request + pull_request_review triggers
while keeping improvements (frontier_amd matrix, concurrency group,
timeout, run_parallel_benchmarks.sh).

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: sbryngelson

.github/workflows/bench.yml

@@ -1,85 +1,35 @@
 name: 'Benchmark'
 
 on:
-  # Trigger when Test Suite completes (no polling needed)
-  workflow_run:
-    workflows: ["Test Suite"]
-    types: [completed]
+  pull_request:
+  pull_request_review:
+    types: [submitted]
   workflow_dispatch:
 
 concurrency:
-  group: ${{ github.workflow }}-${{ github.event.workflow_run.head_branch || github.ref }}
+  group: ${{ github.workflow }}-${{ github.ref }}
   cancel-in-progress: true
 
 jobs:
   file-changes:
     name: Detect File Changes
-    # Only run if Test Suite passed (or manual dispatch)
-    if: github.event_name == 'workflow_dispatch' || github.event.workflow_run.conclusion == 'success'
     runs-on: 'ubuntu-latest'
     outputs:
       checkall: ${{ steps.changes.outputs.checkall }}
-      pr_number: ${{ steps.pr-info.outputs.pr_number }}
-      pr_approved: ${{ steps.pr-info.outputs.approved }}
-      pr_author: ${{ steps.pr-info.outputs.author }}
     steps:
       - name: Clone
         uses: actions/checkout@v4
-        with:
-          ref: ${{ github.event.workflow_run.head_sha || github.sha }}
 
       - name: Detect Changes
         uses: dorny/paths-filter@v3
         id: changes
         with:
           filters: ".github/file-filter.yml"
 
-      - name: Get PR Info
-        id: pr-info
-        env:
-          GH_TOKEN: ${{ github.token }}
-        run: |
-          if [ "${{ github.event_name }}" = "workflow_dispatch" ]; then
-            echo "pr_number=" >> $GITHUB_OUTPUT
-            echo "approved=true" >> $GITHUB_OUTPUT
-            echo "author=${{ github.actor }}" >> $GITHUB_OUTPUT
-          else
-            # Get PR number from workflow_run
-            PR_NUMBER="${{ github.event.workflow_run.pull_requests[0].number }}"
-            if [ -n "$PR_NUMBER" ]; then
-              echo "pr_number=$PR_NUMBER" >> $GITHUB_OUTPUT
-
-              # Fetch actual PR author from API (workflow_run.actor is the re-runner, not PR author)
-              PR_AUTHOR=$(gh api repos/${{ github.repository }}/pulls/$PR_NUMBER --jq '.user.login')
-              echo "author=$PR_AUTHOR" >> $GITHUB_OUTPUT
-
-              # Check if PR is approved
-              APPROVED=$(gh api repos/${{ github.repository }}/pulls/$PR_NUMBER/reviews \
-                --jq '[.[] | select(.state == "APPROVED")] | length')
-              if [ "$APPROVED" -gt 0 ]; then
-                echo "approved=true" >> $GITHUB_OUTPUT
-              else
-                echo "approved=false" >> $GITHUB_OUTPUT
-              fi
-            else
-              echo "pr_number=" >> $GITHUB_OUTPUT
-              echo "approved=false" >> $GITHUB_OUTPUT
-              echo "author=" >> $GITHUB_OUTPUT
-            fi
-          fi
-
   self:
     name: "${{ matrix.name }} (${{ matrix.device }}${{ matrix.interface != 'none' && format('-{0}', matrix.interface) || '' }})"
-    if: >
-      github.repository == 'MFlowCode/MFC' &&
-      needs.file-changes.outputs.checkall == 'true' &&
-      (
-        github.event_name == 'workflow_dispatch' ||
-        needs.file-changes.outputs.pr_approved == 'true' ||
-        needs.file-changes.outputs.pr_author == 'sbryngelson' ||
-        needs.file-changes.outputs.pr_author == 'wilfonba'
-      )
-    needs: [file-changes]
+    if: ${{ github.repository=='MFlowCode/MFC' && needs.file-changes.outputs.checkall=='true' && ((github.event_name=='pull_request_review' && github.event.review.state=='approved') || (github.event_name=='pull_request' && (github.event.pull_request.user.login=='sbryngelson' || github.event.pull_request.user.login=='wilfonba')) || github.event_name=='workflow_dispatch') }}
+    needs: file-changes
     strategy:
       fail-fast: false
       matrix:
@@ -143,7 +93,6 @@ jobs:
       - name: Clone - PR
         uses: actions/checkout@v4
         with:
-          ref: ${{ github.event.workflow_run.head_sha || github.sha }}
           path: pr
 
       - name: Clone - Master
@@ -155,7 +104,7 @@ jobs:
 
       - name: Setup & Build
         if: matrix.build_script != ''
-        run: | 
+        run: |
           (cd pr     && ${{ matrix.build_script }}) &
           (cd master && ${{ matrix.build_script }}) &
           wait %1 && wait %2