ci: self-contained pnpm setup, drop cache-warming job (#771)

Replace the separate `setup` reusable workflow (a serial cache-warming
job that every consumer blocked on via `needs: setup`) with a
self-contained `setup-pnpm` composite that installs dependencies using
actions/setup-node's built-in, lockfile-keyed pnpm store cache.

- Rewrite .github/actions/setup-pnpm to setup pnpm + Node (cache: pnpm)
  then `pnpm install --frozen-lockfile`, instead of a restore-only step
  with no install fallback.
- Delete .github/workflows/setup.yml and remove `needs: setup` from
  test, check-dist, update (3 jobs), and sync-readme-versions. Jobs now
  run in parallel without waiting on a warm-up runner.
- Move the repository guard from the removed setup job onto the sync
  job in sync-readme-versions.
- Drops the redundant `needs: setup` on update's schema job, which only
  runs curl + jq and never used pnpm (was #3).

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: andykenward

.github/actions/setup-pnpm/action.yml

@@ -1,7 +1,7 @@
 # yaml-language-server: $schema=https://json.schemastore.org/github-action.json
 
-name: 'Restore pnpm cache'
-description: 'Sets up Node and pnpm, restores node_modules and ~/.cache/ from cache (no install)'
+name: 'Setup pnpm'
+description: 'Sets up Node and pnpm with lockfile-keyed store caching, then installs dependencies'
 inputs:
   node-version:
     description: 'Version of Node'
@@ -10,13 +10,11 @@ inputs:
 runs:
   using: 'composite'
   steps:
-    - uses: pnpm/action-setup@8912a9102ac27614460f54aedde9e1e7f9aec20d #v6.0.5
+    - uses: pnpm/action-setup@0e279bb959325dab635dd2c09392533439d90093 #v6.0.8
     - uses: actions/setup-node@48b55a011bda9f5d6aeb4c2d9c7362e8dae4041e #v6.4.0
       with:
         node-version: ${{ inputs.node-version }}
-    - uses: actions/cache/restore@27d5ce7f107fe9357f9df03efb73ab90386fccae #v5.0.5
-      with:
-        path: |
-          node_modules
-          ~/.cache/
-        key: ${{ runner.os }}-node-${{ hashFiles('pnpm-lock.yaml') }}
+        cache: pnpm
+    - name: Install dependencies
+      shell: bash
+      run: pnpm install --frozen-lockfile

.github/workflows/check-dist.yml

@@ -27,10 +27,7 @@ concurrency:
   cancel-in-progress: true
 
 jobs:
-  setup:
-    uses: ./.github/workflows/setup.yml
   check-dist:
-    needs: setup
     runs-on: ubuntu-latest
     timeout-minutes: 5
     steps:

.github/workflows/setup.yml

@@ -15,13 +15,8 @@ concurrency:
 permissions: {}
 
 jobs:
-  setup:
-    if: ${{ github.repository == 'andykenward/github-actions-cloudflare-pages' }}
-    permissions:
-      contents: read
-    uses: ./.github/workflows/setup.yml
   sync:
-    needs: setup
+    if: ${{ github.repository == 'andykenward/github-actions-cloudflare-pages' }}
     name: Sync action version references
     runs-on: ubuntu-latest
     permissions:

.github/workflows/sync-readme-versions.yml

@@ -17,10 +17,7 @@ concurrency:
   cancel-in-progress: true
 
 jobs:
-  setup:
-    uses: ./.github/workflows/setup.yml
   test:
-    needs: setup
     runs-on: ubuntu-latest
     timeout-minutes: 5
     steps:

.github/workflows/test.yml

@@ -12,12 +12,7 @@ concurrency:
 permissions: {}
 
 jobs:
-  setup:
-    permissions:
-      contents: read
-    uses: ./.github/workflows/setup.yml
   download:
-    needs: setup
     permissions:
       contents: write
       pull-requests: write
@@ -52,7 +47,6 @@ jobs:
           body: |
             This is an automated PR to update payloads.
   types:
-    needs: setup
     permissions:
       contents: write
       pull-requests: write
@@ -85,7 +79,6 @@ jobs:
           body: |
             This is an automated PR to update generated types.
   schema:
-    needs: setup
     permissions:
       contents: write
       pull-requests: write