fix: use test-ci in CI workflow for correct build environment

The separate build + test:unit steps caused snapshot mismatches because
pnpm build does not set VITEST=1, which gets inlined at build time.
Using test-ci runs test:prepare (which builds with .env.test setting
VITEST=1) followed by test:unit, matching local test behavior.

Author: mtorp

.github/workflows/ci.yml

@@ -45,8 +45,5 @@ jobs:
         with:
           node-version: ${{ matrix.node-version }}
 
-      - name: Build
-        run: pnpm run build
-
-      - name: Run unit tests
-        run: pnpm test:unit
+      - name: Build and run unit tests
+        run: pnpm test-ci