✨ feat: implement schema-per-scenario isolation for BDD tests

- Add BDD_SCHEMA_ISOLATION env var to enable schema-per-scenario mode
- Generate unique schema names using SHA256 hash of feature+scenario
- Implement SetupScenarioSchema() and TeardownScenarioSchema() methods
- Handle search_path configuration for schema isolation
- Use CASCADE drop to clean up all scenario-created DB objects
- Add isSchemaIsolationEnabled() helper to suite.go
- Update cleanup flow: skip table clearing when schema isolation is active
- Add ADR 0025 documenting isolation strategies and decision rationale

Activation: Set BDD_SCHEMA_ISOLATION=true to enable
Debug: Set BDD_ENABLE_CLEANUP_LOGS=true for verbose isolation logging

Generated by Mistral Vibe.
Co-Authored-By: Mistral Vibe <vibe@mistral.ai>

pkg/bdd/suite.go

@@ -20,6 +20,11 @@ func isCleanupLoggingEnabled() bool {
 	return os.Getenv("BDD_ENABLE_CLEANUP_LOGS") == "true"
 }
 
+// isSchemaIsolationEnabled returns true if BDD_SCHEMA_ISOLATION environment variable is set to "true"
+func isSchemaIsolationEnabled() bool {
+	return os.Getenv("BDD_SCHEMA_ISOLATION") == "true"
+}
+
 func InitializeTestSuite(ctx *godog.TestSuiteContext) {
 	ctx.BeforeSuite(func() {
 		// Small delay to ensure any previous server instances are fully cleaned up
@@ -37,8 +42,24 @@ func InitializeTestSuite(ctx *godog.TestSuiteContext) {
 
 	sc := ctx.ScenarioContext()
 	sc.BeforeScenario(func(s *godog.Scenario) {
+		// Get feature name from context or environment
+		feature := os.Getenv("FEATURE")
+		if feature == "" {
+			// Try to extract feature from scenario tags or path
+			feature = "unknown"
+		}
+
 		if isCleanupLoggingEnabled() {
-			log.Info().Str("scenario", s.Name).Msg("CLEANUP: Scenario starting")
+			log.Info().Str("feature", feature).Str("scenario", s.Name).Msg("CLEANUP: Scenario starting")
+		}
+
+		// Setup schema isolation if enabled
+		if sharedServer != nil {
+			if err := sharedServer.SetupScenarioSchema(feature, s.Name); err != nil {
+				if isCleanupLoggingEnabled() {
+					log.Warn().Err(err).Msg("ISOLATION: Failed to setup scenario schema")
+				}
+			}
 		}
 	})
 
@@ -48,17 +69,27 @@ func InitializeTestSuite(ctx *godog.TestSuiteContext) {
 		}
 
 		if sharedServer != nil {
+			// Teardown schema isolation if enabled
+			if teardownErr := sharedServer.TeardownScenarioSchema(); teardownErr != nil {
+				if isCleanupLoggingEnabled() {
+					log.Warn().Err(teardownErr).Msg("ISOLATION: Failed to teardown scenario schema")
+				}
+			}
+
 			// Reset JWT secrets after every scenario to prevent pollution
+			// Note: This is still needed for in-memory state even with schema isolation
 			if resetErr := sharedServer.ResetJWTSecrets(); resetErr != nil {
 				if isCleanupLoggingEnabled() {
 					log.Warn().Err(resetErr).Msg("CLEANUP: Failed to reset JWT secrets after scenario")
 				}
 			}
 
-			// Clean database after every scenario
-			if cleanupErr := sharedServer.CleanupDatabase(); cleanupErr != nil {
-				if isCleanupLoggingEnabled() {
-					log.Warn().Err(cleanupErr).Msg("CLEANUP: Failed to cleanup database after scenario")
+			// Clean database after every scenario (only if schema isolation is disabled)
+			if !isSchemaIsolationEnabled() {
+				if cleanupErr := sharedServer.CleanupDatabase(); cleanupErr != nil {
+					if isCleanupLoggingEnabled() {
+						log.Warn().Err(cleanupErr).Msg("CLEANUP: Failed to cleanup database after scenario")
+					}
 				}
 			}
 		}