chore(vendor): import pi 0.85.1

Imported as a linear vendor commit so forge rebases do not replay the upstream root tree.

git-subtree-dir: third_party/pi

git-subtree-split: d981de1229ef899957bbe968bc8dcda02a21f477

third_party/pi/.github/workflows/npm-audit.yml

@@ -0,0 +1,31 @@
+name: npm audit
+
+on:
+  schedule:
+    - cron: '37 7 * * *'
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+jobs:
+  audit:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
+
+      - name: Setup Node.js
+        uses: actions/setup-node@820762786026740c76f36085b0efc47a31fe5020 # v7.0.0
+        with:
+          node-version: 22
+          cache: npm
+
+      - name: Install dependencies without lifecycle scripts
+        run: npm ci --ignore-scripts --no-audit --no-fund
+
+      - name: Audit production vulnerabilities
+        run: npm audit --omit=dev --audit-level=moderate
+
+      - name: Verify registry signatures
+        run: npm audit signatures --omit=dev