ci: add proper error handling for Kiwi installation verification

Add explicit checks with clear error messages to identify why the
Kiwi C library installation is failing in CI. The script now:

- Verifies headers exist at /usr/local/include/kiwi/
- Verifies libraries exist at /usr/local/lib/libkiwi*
- Fails fast with descriptive error messages if verification fails
- Shows success confirmation when installation works properly

This will help identify whether the issue is with sudo permissions,
path differences between local and CI environments, or other
installation problems specific to GitHub Actions runners.

Author: kkweon

.github/workflows/ci.yaml

@@ -20,5 +20,23 @@ jobs:
         with:
           go-version: ${{ matrix.go-version }}
       - uses: actions/checkout@v4
-      - run: make install-kiwi
-      - run: make test
+      - name: Install Kiwi dependencies
+        run: |
+          echo "Installing Kiwi C library..."
+          make install-kiwi
+          echo "Verifying installation..."
+          if [ ! -d "/usr/local/include/kiwi" ]; then
+            echo "ERROR: Kiwi headers not found at /usr/local/include/kiwi/"
+            echo "Installation failed - headers were not properly installed"
+            exit 1
+          fi
+          if ! ls /usr/local/lib/libkiwi* > /dev/null 2>&1; then
+            echo "ERROR: Kiwi libraries not found at /usr/local/lib/libkiwi*"
+            echo "Installation failed - libraries were not properly installed"
+            exit 1
+          fi
+          echo "✓ Kiwi installation verified successfully"
+          ls -la /usr/local/include/kiwi/
+          ls -la /usr/local/lib/libkiwi*
+      - name: Run tests
+        run: make test