🧪 test: add JWT secret rotation BDD scenarios and step implementations (#12)

✨ merge: implement JWT secret rotation with BDD scenario isolation

- Implement JWT secret rotation mechanism (closes #8)
- Add per-scenario state isolation for BDD tests (closes #14)
- Validate password reset workflow via BDD tests (closes #7)
- Fix port conflicts in test validation
- Add state tracer for debugging test execution
- Document BDD isolation strategies in ADR 0025
- Fix PostgreSQL configuration environment variables

Generated by Mistral Vibe.
Co-Authored-By: Mistral Vibe <vibe@mistral.ai>
Co-authored-by: Gabriel Radureau <arcodange@gmail.com>
Co-committed-by: Gabriel Radureau <arcodange@gmail.com>

features/greet/greet.feature

@@ -0,0 +1,37 @@
+# features/greet.feature
+@greet @smoke
+Feature: Greet Service
+  The greet service should return appropriate greetings
+
+  @basic
+  Scenario: Default greeting
+    Given the server is running
+    When I request the default greeting
+    Then the response should be "{\"message\":\"Hello world!\"}"
+
+  @basic
+  Scenario: Personalized greeting
+    Given the server is running
+    When I request a greeting for "John"
+    Then the response should be "{\"message\":\"Hello John!\"}"
+
+  @v2 @api
+  Scenario: v2 greeting with JSON POST request
+    Given the server is running with v2 enabled
+    When I send a POST request to v2 greet with name "John"
+    Then the response should be "{\"message\":\"Hello my friend John!\"}"
+
+  Scenario: v2 default greeting with empty name
+    Given the server is running with v2 enabled
+    When I send a POST request to v2 greet with name ""
+    Then the response should be "{\"message\":\"Hello my friend!\"}"
+
+  Scenario: v2 greeting with missing name field
+    Given the server is running with v2 enabled
+    When I send a POST request to v2 greet with invalid JSON "{}"
+    Then the response should be "{\"message\":\"Hello my friend!\"}"
+
+  Scenario: v2 greeting with name that is too long
+    Given the server is running with v2 enabled
+    When I send a POST request to v2 greet with name "ThisNameIsWayTooLongAndShouldFailValidationBecauseItExceedsTheMaximumAllowedLengthOf100Characters!!!!"
+    Then the response should contain error "validation_failed"

features/greet/greet_test.go

@@ -0,0 +1,30 @@
+package greet
+
+import (
+	"os"
+	"testing"
+
+	"dance-lessons-coach/pkg/bdd/testsetup"
+)
+
+func TestGreetBDD(t *testing.T) {
+	// Test suite with v2 disabled - run non-v2 scenarios only
+	t.Run("v1", func(t *testing.T) {
+		os.Setenv("GODOG_TAGS", "~@v2 && ~@skip")
+		config := testsetup.NewFeatureConfig("greet", "progress", false)
+		suite := testsetup.CreateTestSuite(t, config, "dance-lessons-coach BDD Tests - Greet Feature v1")
+		if suite.Run() != 0 {
+			t.Fatal("non-zero status returned, failed to run greet BDD tests with v2 disabled")
+		}
+	})
+
+	// Test suite with v2 enabled - run v2 scenarios only
+	t.Run("v2", func(t *testing.T) {
+		os.Setenv("GODOG_TAGS", "@v2 && ~@skip")
+		config := testsetup.NewFeatureConfig("greet", "progress", false)
+		suite := testsetup.CreateTestSuite(t, config, "dance-lessons-coach BDD Tests - Greet Feature v2")
+		if suite.Run() != 0 {
+			t.Fatal("non-zero status returned, failed to run greet BDD tests with v2 enabled")
+		}
+	})
+}