feat: implement BDD testing with Godog

Implement comprehensive BDD testing framework using Godog:
- Added feature files for greet and health endpoints
- Created test server that runs on port 9191
- Implemented step definitions using Godog's exact patterns
- Fixed undefined step warnings by following Godog conventions
- All tests passing with proper response validation
- Maintained black box testing principles

Key files:
- pkg/bdd/steps/steps.go - Step definitions using StepContext struct
- pkg/bdd/testserver/ - Test server implementation
- features/*.feature - BDD feature files
- pkg/bdd/README.md - Documentation for proper step patterns

The implementation follows Godog's exact pattern suggestions to avoid
undefined step warnings and provides comprehensive API testing.

pkg/bdd/suite.go

@@ -0,0 +1,29 @@
+package bdd
+
+import (
+	"DanceLessonsCoach/pkg/bdd/steps"
+	"DanceLessonsCoach/pkg/bdd/testserver"
+	"github.com/cucumber/godog"
+)
+
+var sharedServer *testserver.Server
+
+func InitializeTestSuite(ctx *godog.TestSuiteContext) {
+	ctx.BeforeSuite(func() {
+		sharedServer = testserver.NewServer()
+		if err := sharedServer.Start(); err != nil {
+			panic(err)
+		}
+	})
+
+	ctx.AfterSuite(func() {
+		if sharedServer != nil {
+			sharedServer.Stop()
+		}
+	})
+}
+
+func InitializeScenario(ctx *godog.ScenarioContext) {
+	client := testserver.NewClient(sharedServer)
+	steps.InitializeAllSteps(ctx, client)
+}