chore(#846): remove unused PR-size labeler (size/S–XL) workflow (#848)

The PR Gate workflow's only job, size-check, labeled every PR with
size/S–size/XL based on lines changed. Those labels aren't used in any
review, triage, or automation flow, so the workflow was pure noise.

- Delete .github/workflows/pr-gate.yml
- Drop size-check from required status checks in both rulesets so PRs
  don't block forever on a check that never reports
- Remove pr-gate.yml from INERT_WORKFLOWS (ci-test-scope.cjs) and the
  knownInert list (ci-test-scope.test.cjs)
- Remove "PR Gate / size-check" from setup-branch-protection.sh

Closes #846

Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>

.github/rulesets/main-protection.json

@@ -35,7 +35,6 @@
         "strict_required_status_checks_policy": true,
         "required_status_checks": [
           { "context": "Required tests" },
-          { "context": "size-check" },
           { "context": "check-branch" },
           { "context": "changeset-lint" },
           { "context": "docs-lint" },

.github/rulesets/release-branches.json

@@ -32,7 +32,6 @@
         "strict_required_status_checks_policy": true,
         "required_status_checks": [
           { "context": "Required tests" },
-          { "context": "size-check" },
           { "context": "check-branch" },
           { "context": "changeset-lint" },
           { "context": "docs-lint" },

.github/workflows/pr-gate.yml

@@ -1,71 +0,0 @@
-name: PR Gate
-
-on:
-  pull_request:
-    types: [opened, synchronize]
-
-concurrency:
-  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.ref }}
-  cancel-in-progress: true
-
-permissions:
-  pull-requests: write
-  issues: write
-
-jobs:
-  size-check:
-    runs-on: ubuntu-latest
-    timeout-minutes: 2
-    steps:
-      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd  # v6.0.2
-        with:
-          fetch-depth: 0
-
-      - name: Check PR size
-        uses: actions/github-script@3a2844b7e9c422d3c10d287c895573f7108da1b3 # v9.0.0
-        with:
-          script: |
-            const files = await github.paginate(github.rest.pulls.listFiles, {
-              owner: context.repo.owner,
-              repo: context.repo.repo,
-              pull_number: context.issue.number,
-              per_page: 100,
-            });
-
-            const additions = files.reduce((sum, f) => sum + f.additions, 0);
-            const deletions = files.reduce((sum, f) => sum + f.deletions, 0);
-            const total = additions + deletions;
-
-            let label = '';
-            if (total <= 50) label = 'size/S';
-            else if (total <= 200) label = 'size/M';
-            else if (total <= 500) label = 'size/L';
-            else label = 'size/XL';
-
-            // Remove existing size labels
-            const existingLabels = context.payload.pull_request.labels || [];
-            const sizeLabels = existingLabels.filter(l => l.name.startsWith('size/'));
-            for (const staleLabel of sizeLabels) {
-              await github.rest.issues.removeLabel({
-                owner: context.repo.owner,
-                repo: context.repo.repo,
-                issue_number: context.issue.number,
-                name: staleLabel.name
-              }).catch(() => {}); // ignore if already removed
-            }
-
-            // Add size label
-            try {
-              await github.rest.issues.addLabels({
-                owner: context.repo.owner,
-                repo: context.repo.repo,
-                issue_number: context.issue.number,
-                labels: [label],
-              });
-            } catch (e) {
-              core.warning(`Could not add label: ${e.message}`);
-            }
-
-            if (total > 500) {
-              core.warning(`Large PR: ${total} lines changed (${additions}+ / ${deletions}-). Consider splitting.`);
-            }

scripts/ci-test-scope.cjs

@@ -20,7 +20,6 @@ const INERT_WORKFLOWS = new Set([
   'auto-backmerge.yml',
   'close-draft-prs.yml',
   'dismiss-unauthorized-pr-approvals.yml',
-  'pr-gate.yml',
   'pr-target-validator.yml',
   'pr-template-format.yml',
   'require-issue-link.yml',

scripts/setup-branch-protection.sh

@@ -61,13 +61,11 @@ REQUIRED_CHECKS_MAIN=(
   "security-scan"
   "Changeset Required / changeset-lint"
   "Docs Required / docs-lint"
-  "PR Gate / size-check"
   "Validate Branch Name / check-branch"
 )
 
 REQUIRED_CHECKS_NEXT=(
   "test"
-  "PR Gate / size-check"
   "Validate Branch Name / check-branch"
   "Changeset Required / changeset-lint"
   "Docs Required / docs-lint"

tests/ci-test-scope.test.cjs

@@ -343,7 +343,7 @@ describe('INERT_WORKFLOWS allowlist integrity guard', () => {
   const knownInert = [
     'stale.yml', 'branch-cleanup.yml', 'branch-naming.yml', 'auto-label-issues.yml',
     'auto-branch.yml', 'auto-backmerge.yml', 'close-draft-prs.yml',
-    'dismiss-unauthorized-pr-approvals.yml', 'pr-gate.yml', 'pr-target-validator.yml',
+    'dismiss-unauthorized-pr-approvals.yml', 'pr-target-validator.yml',
     'pr-template-format.yml', 'require-issue-link.yml', 'changeset-required.yml',
     'docs-required.yml', 'discord-changelog.yml',
   ];