workflows/{labels,reviewers}: move from Eval to PR context

This allows *not* depending on those two jobs with the required status
checks in the next commit, which wouldn't really make sense. If labeling
or pinging maintainers fails for obscure reasons or because the GitHub
API is down, a PR might still pass all other tests and be
merge-eligible.

(cherry picked from commit 9927d758e7)

.github/workflows/eval.yml

@@ -135,8 +135,6 @@ jobs:
     needs: [eval]
     if: inputs.targetSha
     permissions:
-      issues: write # needed to create *new* labels
-      pull-requests: write
       statuses: write
     steps:
       - name: Download output paths and eval stats for all systems
@@ -217,25 +215,6 @@ jobs:
               target_url
             })
 
-  labels:
-    name: Labels
-    needs: [compare]
-    uses: ./.github/workflows/labels.yml
-    permissions:
-      issues: write
-      pull-requests: write
-
-  reviewers:
-    name: Reviewers
-    # No dependency on "compare", so that it can start at the same time.
-    # We only wait for the "comparison" artifact to be available, which makes the start-to-finish time
-    # for the eval workflow considerably faster.
-    needs: [eval]
-    if: inputs.targetSha
-    uses: ./.github/workflows/reviewers.yml
-    secrets:
-      OWNER_APP_PRIVATE_KEY: ${{ secrets.OWNER_APP_PRIVATE_KEY }}
-
   misc:
     if: ${{ github.event_name != 'push' }}
     runs-on: ubuntu-24.04-arm

.github/workflows/pr.yml

@@ -60,8 +60,6 @@ jobs:
     uses: ./.github/workflows/eval.yml
     permissions:
       # compare
-      issues: write
-      pull-requests: write
       statuses: write
     secrets:
       OWNER_APP_PRIVATE_KEY: ${{ secrets.OWNER_APP_PRIVATE_KEY }}
@@ -70,6 +68,22 @@ jobs:
       targetSha: ${{ needs.prepare.outputs.targetSha }}
       systems: ${{ needs.prepare.outputs.systems }}
 
+  labels:
+    name: Labels
+    needs: [eval]
+    uses: ./.github/workflows/labels.yml
+    permissions:
+      issues: write
+      pull-requests: write
+
+  reviewers:
+    name: Reviewers
+    needs: [prepare, eval]
+    if: needs.prepare.outputs.targetSha
+    uses: ./.github/workflows/reviewers.yml
+    secrets:
+      OWNER_APP_PRIVATE_KEY: ${{ secrets.OWNER_APP_PRIVATE_KEY }}
+
   build:
     name: Build
     needs: [prepare]