refactor: adopt feature package boundaries and JPA

docs/tests/integration/smtp-onboarding.md

@@ -3,7 +3,7 @@
 - **Test type:** Integration
 - **Requirement IDs:** `INT-001–INT-008, ACC-011, SEC-001`
 - **Scenario IDs:** `AC-INT-001, AC-INT-002, AC-ACC-004`
-- **Test class/method:** `com.lab.labtimesheet.SmtpIntegrationTest.failedSmtpTestNeverActivatesDraftAndSecretsRemainEncrypted`
+- **Test class/method:** `com.lab.labtimesheet.feature.integration.service.SmtpIntegrationTest.failedSmtpTestNeverActivatesDraftAndSecretsRemainEncrypted`
 - **Implementation commit:** `this milestone commit`
 
 ## Protected behavior
@@ -12,7 +12,7 @@ SMTP credentials are AES-256-GCM encrypted, only a successfully tested draft can
 
 ## Test method
 
-The test persists a draft against PostgreSQL 18.4 using a deterministic test-only master key and a recording SMTP boundary. It forces send failure, inspects database state, rejects activation, then allows the probe and activates the tested draft.
+The test persists a draft through Spring Data JPA against PostgreSQL 18.4 using a deterministic test-only master key and a recording SMTP boundary. It forces send failure, inspects database state, rejects activation, then allows the probe and activates the tested draft.
 
 ## Hand-derived expected result
 
@@ -26,7 +26,7 @@ Ciphertext must not contain the submitted password. Failure leaves `status=DRAFT
 export JAVA_HOME=/opt/homebrew/opt/openjdk@25
 export PATH="$JAVA_HOME/bin:/opt/homebrew/opt/node@24/bin:$PATH"
 export DOCKER_HOST=unix:///Users/sechmachine/.orbstack/run/docker.sock
-./mvnw -Dtest=BootstrapIntegrationTest,SmtpAccountIntegrationTest test
+./mvnw -Dtest=SmtpIntegrationTest test
 ```
 
 **Observed result**
@@ -54,7 +54,7 @@ export DOCKER_HOST=unix:///Users/sechmachine/.orbstack/run/docker.sock
 **Observed result**
 
 ```text
-Tests run: 3, Failures: 0, Errors: 0, Skipped: 0
+Tests run: 1, Failures: 0, Errors: 0, Skipped: 0
 BUILD SUCCESS
 ```