ci: fix Windows cache restore to only use dist artifacts

Split cache restore into OS-specific steps:
- Linux: Restore both dist and node_modules from cache
- Windows: Only restore dist (node_modules are platform-specific)

Windows then runs pnpm install to create its own node_modules.
This prevents cache miss failures on Windows test jobs.

Author: jdalton

.github/workflows/ci.yml

@@ -104,7 +104,8 @@ jobs:
           node-version: ${{ matrix.node }}
           cache: 'pnpm'
 
-      - name: Restore build artifacts
+      - name: Restore build artifacts (Linux)
+        if: runner.os == 'Linux'
         uses: actions/cache/restore@0057852bfaa89a56745cba8c7296529d2fc39830 # v4.3.0
         with:
           path: |
@@ -113,6 +114,14 @@ jobs:
           key: build-${{ github.sha }}-Linux
           fail-on-cache-miss: true
 
+      - name: Restore build artifacts (Windows)
+        if: runner.os == 'Windows'
+        uses: actions/cache/restore@0057852bfaa89a56745cba8c7296529d2fc39830 # v4.3.0
+        with:
+          path: dist
+          key: build-${{ github.sha }}-Linux
+          fail-on-cache-miss: true
+
       - name: Install dependencies (Windows)
         if: runner.os == 'Windows'
         run: pnpm install --frozen-lockfile