✨ feat: add schema-per-scenario isolation with BDD_SCHEMA_ISOLATION env var

- Add BDD_SCHEMA_ISOLATION env var to enable PostgreSQL schema-per-scenario isolation
- Generate unique schema names: test_{sha256(feature:scenario)[:8]}
- Implement SetupScenarioSchema() and TeardownScenarioSchema() with search_path handling
- Add CASCADE drop to clean up all scenario-created DB objects
- Add isSchemaIsolationEnabled() helpers to both suite.go and server.go
- Skip table clearing when schema isolation is active (schema drop replaces it)
- Update validate-test-suite.sh to set FIXED_TEST_PORT and BDD_SCHEMA_ISOLATION
- Add isCleanupLoggingEnabled() for optional CLEANUP: prefixed logs
- Add ADR 0025 documenting all isolation strategies and decision rationale

Activation:
  BDD_SCHEMA_ISOLATION=true - Enable schema-per-scenario isolation
  BDD_ENABLE_CLEANUP_LOGS=true - Enable verbose cleanup/isolation logging

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

pkg/bdd/suite.go

@@ -42,11 +42,10 @@ func InitializeTestSuite(ctx *godog.TestSuiteContext) {
 
 	sc := ctx.ScenarioContext()
 	sc.BeforeScenario(func(s *godog.Scenario) {
-		// Get feature name from context or environment
+		// Get feature name from environment - falls back to "bdd" for multi-feature tests
 		feature := os.Getenv("FEATURE")
 		if feature == "" {
-			// Try to extract feature from scenario tags or path
-			feature = "unknown"
+			feature = "bdd"
 		}
 
 		if isCleanupLoggingEnabled() {
@@ -55,9 +54,14 @@ func InitializeTestSuite(ctx *godog.TestSuiteContext) {
 
 		// Setup schema isolation if enabled
 		if sharedServer != nil {
-			if err := sharedServer.SetupScenarioSchema(feature, s.Name); err != nil {
+			// Include scenario Uri for disambiguation when multiple features run
+			scenarioKey := s.Name
+			if s.Uri != "" {
+				scenarioKey = fmt.Sprintf("%s:%s", s.Uri, s.Name)
+			}
+			if err := sharedServer.SetupScenarioSchema(feature, scenarioKey); err != nil {
 				if isCleanupLoggingEnabled() {
-					log.Warn().Err(err).Msg("ISOLATION: Failed to setup scenario schema")
+					log.Warn().Err(err).Str("feature", feature).Str("scenario", scenarioKey).Msg("ISOLATION: Failed to setup scenario schema")
 				}
 			}
 		}