chore(testing): Setup new self-hosted test runner (#6067)

.github/workflows/playwright.yml

@@ -23,7 +23,7 @@ concurrency:
 jobs:
   playwright-tests:
     timeout-minutes: 120
-    runs-on: self-hosted
+    runs-on: [self-hosted, nashua]
     strategy:
       fail-fast: false
       matrix:
@@ -32,14 +32,6 @@ jobs:
       - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6.0.3
         with:
           persist-credentials: false
-      # Self-hosted runner hygiene: wipe any stale/corrupted pnpm self-install
-      # before action-setup reinstalls it. A prior `cache: pnpm` restore left a
-      # pnpm install missing dist/worker.js, breaking `pnpm install`. Plain shell
-      # so it runs even when pnpm itself is broken. Cheap: action-setup reinstalls.
-      - name: Reset stale pnpm self-install
-        shell: bash
-        run: rm -rf "$HOME/setup-pnpm"
-      - uses: pnpm/action-setup@0e279bb959325dab635dd2c09392533439d90093 # v6.0.8
       - uses: actions/setup-node@48b55a011bda9f5d6aeb4c2d9c7362e8dae4041e # v6.4.0
         with:
           node-version: ${{ matrix.node-version }}
@@ -47,6 +39,19 @@ jobs:
           # pnpm store on local disk. The Actions cache doesn't preserve the
           # pnpm self-install's links faithfully, dropping pnpm/dist/worker.js
           # and breaking `pnpm install` with MODULE_NOT_FOUND.
+      # Install pnpm via Corepack instead of pnpm/action-setup. The action's
+      # self-installer is a JS action run under the runner's bundled
+      # externals/node{version} and derives the `npm` path from that runtime — which
+      # on this self-hosted runner is corrupted (Cannot find module
+      # '../lib/cli.js'), so it dies regardless of `standalone:true`. Corepack
+      # ships inside the Node that setup-node just installed, reads the pinned
+      # `packageManager` (pnpm@11.5.2) from package.json, and fetches pnpm via
+      # Node's own https — it never invokes the npm CLI.
+      - name: Enable Corepack (pnpm)
+        shell: bash
+        run: |
+          corepack enable
+          corepack prepare --activate
 
       # ── CS3D integration: detect label and ref type ──────────────────────
       - name: Check for CS3D integration label
@@ -119,7 +124,12 @@ jobs:
 
       # ── Common: run tests ───────────────────────────────────────────────
       - name: Install Playwright browsers
-        run: npx playwright install
+        # Only chromium is used (see playwright.config.ts and tests/globalSetup.ts);
+        # firefox/webkit projects are commented out. Scoping the install to chromium
+        # avoids downloading + dep-validating browsers we never launch (the WebKit
+        # validation is what surfaces the "missing libwoff1/libflite1/..." error on
+        # hosts without those libs).
+        run: npx playwright install chromium
       - name: Run Playwright tests
         run: |
           export NODE_OPTIONS="--max_old_space_size=10192"
@@ -161,7 +171,8 @@ jobs:
           fi
           node .scripts/log-build-context.mjs
         env:
-          BUILD_TYPE: ${{ steps.cs3d-ref.outputs.type == 'branch' && 'ohif-downstream' || 'ohif-upstream' }}
+          BUILD_TYPE:
+            ${{ steps.cs3d-ref.outputs.type == 'branch' && 'ohif-downstream' || 'ohif-upstream' }}
           CS3D_REF_TYPE: ${{ steps.cs3d-ref.outputs.type }}
 
       - name: Build OHIF viewer (CS3D preview)
@@ -203,7 +214,7 @@ jobs:
 
   # ── Separate job: block merge when using a CS3D branch ─────────────
   cs3d-branch-merge-guard:
-    name: "CS3D Branch Merge Guard"
+    name: 'CS3D Branch Merge Guard'
     runs-on: ubuntu-latest
     timeout-minutes: 5
     steps: