Switch to runner with more CPU and RAM (#45)

## Motivation for the change, related issues

We are currently having issues with some CI jobs be terminated
prematurely.

## Implementation details

This PR switches the CI workflow to use the
`wordpress-playground-private` runner which has 16 cores and 64GB RAM.

## Testing Instructions (or ideally a Blueprint)

- CI

Author: brandonpayton

.github/workflows/ci.yml

@@ -15,7 +15,7 @@ jobs:
     # take ~25s just to run git clone and restore node_modules.
     lint-and-typecheck:
         name: 'Lint and typecheck'
-        runs-on: ubuntu-latest
+        runs-on: wordpress-playground-private
         steps:
             - uses: actions/checkout@v4
               with:
@@ -25,7 +25,7 @@ jobs:
             - run: npx nx affected --target=typecheck
     lint-and-test-php:
         name: 'Lint and test PHP'
-        runs-on: ubuntu-latest
+        runs-on: wordpress-playground-private
         steps:
             - uses: actions/checkout@v4
               with:
@@ -49,7 +49,7 @@ jobs:
             - run: npx nx run playground-data-liberation:lint:php
             - run: npx nx run playground-data-liberation:test:phpunit
     test-unit-asyncify:
-        runs-on: ubuntu-latest
+        runs-on: wordpress-playground-private
         needs: [lint-and-typecheck]
         steps:
             - uses: actions/checkout@v4
@@ -75,7 +75,7 @@ jobs:
     #               node-version: 23.0.0-nightly2024100909d10b50dc
     #         - run: node --experimental-wasm-jspi --experimental-wasm-stack-switching --expose-gc node_modules/nx/bin/nx affected --target=test --configuration=ci
     test-e2e:
-        runs-on: ubuntu-latest
+        runs-on: wordpress-playground-private
         needs: [lint-and-typecheck]
         # Run as root to allow node to bind to port 80
         steps:
@@ -93,7 +93,7 @@ jobs:
                   path: dist/cypress/packages/playground/website/screenshots
 
     test-e2e-playwright-prepare:
-        runs-on: ubuntu-latest
+        runs-on: wordpress-playground-private
         needs: [lint-and-typecheck]
         steps:
             - uses: actions/checkout@v4
@@ -112,7 +112,7 @@ jobs:
                   name: playwright-dist
                   path: dist.zip
     test-e2e-playwright:
-        runs-on: ubuntu-latest
+        runs-on: wordpress-playground-private
         needs: [test-e2e-playwright-prepare]
         strategy:
             fail-fast: false
@@ -156,7 +156,7 @@ jobs:
                   name: playwright-dist
 
     build:
-        runs-on: ubuntu-latest
+        runs-on: wordpress-playground-private
         needs: [lint-and-typecheck]
         steps:
             - uses: actions/checkout@v4
@@ -187,7 +187,7 @@ jobs:
             url: ${{ steps.deployment.outputs.page_url }}
 
         # Specify runner + deployment step
-        runs-on: ubuntu-latest
+        runs-on: wordpress-playground-private
         steps:
             - uses: actions/checkout@v4
               with: