fix(ci): pass CI=true to Alpine Docker container for musl E2E

The snap test runner passes CI through to subprocesses, and vp
commands may behave differently in CI mode.

Author: fengmk2

.github/workflows/ci.yml

@@ -650,6 +650,7 @@ jobs:
       - name: Run E2E in Alpine container
         run: |
           docker run --rm \
+            -e CI=true \
             -v "${{ github.workspace }}:/workspace" \
             -w /workspace \
             node:22-alpine3.21 sh -c "