Add comprehensive test suite for current implementation

- Add tests for internal/config package (90.9% coverage)
  - Test all viperConfig getter methods
  - Test LoadConfig with default and environment-specific configs
  - Test error handling for missing config files

- Add tests for internal/di package (88.1% coverage)
  - Test Container lifecycle (NewContainer, Start, Stop)
  - Test providers (ProvideConfig, ProvideLogger, CoreModule)
  - Test lifecycle hooks registration
  - Include mock implementations for testing

- Add tests for internal/logger package (96.5% coverage)
  - Test zapLogger with JSON and console formats
  - Test all logging levels and methods
  - Test middleware (RequestIDMiddleware, LoggingMiddleware)
  - Test context helper functions
  - Include benchmark tests

- Update CI workflow to skip tests when no test files exist
  - Add conditional test execution based on test file presence
  - Add timeout for test execution
  - Verify build when no tests are present

All tests follow Go best practices with table-driven patterns,
parallel execution where safe, and comprehensive coverage.

.github/workflows/ci.yml

@@ -33,17 +33,35 @@ jobs:
       - name: Verify dependencies
         run: go mod verify
 
+      - name: Check for test files
+        id: check-tests
+        run: |
+          if find . -name "*_test.go" -not -path "./vendor/*" -not -path "./.git/*" | grep -q .; then
+            echo "tests_exist=true" >> $GITHUB_OUTPUT
+          else
+            echo "tests_exist=false" >> $GITHUB_OUTPUT
+            echo "No test files found. Skipping test execution."
+          fi
+
       - name: Run tests
+        if: steps.check-tests.outputs.tests_exist == 'true'
         env:
           CGO_ENABLED: 1
-        run: go test -v -race -coverprofile=coverage.out ./...
+        run: go test -v -race -coverprofile=coverage.out -timeout=5m ./...
 
       - name: Upload coverage
+        if: steps.check-tests.outputs.tests_exist == 'true'
         uses: codecov/codecov-action@v4
         with:
           file: ./coverage.out
           fail_ci_if_error: false
 
+      - name: Verify build (no tests)
+        if: steps.check-tests.outputs.tests_exist == 'false'
+        run: |
+          echo "No tests found. Verifying code compiles instead..."
+          go build ./...
+
   lint:
     name: Lint
     runs-on: ubuntu-latest