fix(platform): address round 2 review findings

src/test/java/com/lab/labtimesheet/config/TimeConfigurationTest.java

@@ -0,0 +1,21 @@
+package com.lab.labtimesheet.config;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import java.time.Clock;
+import java.time.Instant;
+import java.time.LocalDate;
+
+import org.junit.jupiter.api.Test;
+
+class TimeConfigurationTest {
+    @Test
+    void utcInstantAtVietnamMidnightUsesTheNewLocalBusinessDate() {
+        Clock applicationClock = new TimeConfiguration().applicationClock();
+        Instant vietnamMidnight = Instant.parse("2026-08-14T17:00:00Z");
+
+        LocalDate businessDate = LocalDate.now(Clock.fixed(vietnamMidnight, applicationClock.getZone()));
+
+        assertThat(businessDate).isEqualTo(LocalDate.of(2026, 8, 15));
+    }
+}

src/test/java/com/lab/labtimesheet/feature/account/controller/AccountWebIntegrationTest.java

@@ -176,6 +176,37 @@ class AccountWebIntegrationTest {
                 .andExpect(content().string(org.hamcrest.Matchers.containsString("Duplicate Mentor")));
     }
 
+    @Test
+    void duplicateNormalizedStudentCodeIsReportedOnStudentCodeRatherThanEmail() throws Exception {
+        mockMvc.perform(post("/admin/accounts")
+                        .with(user("admin@example.com").roles("ADMIN"))
+                        .with(csrf())
+                        .param("email", "first-intern@example.com")
+                        .param("displayName", "First Intern")
+                        .param("role", "INTERN")
+                        .param("studentCode", "STU-ROUND-2")
+                        .param("internshipStart", "2026-08-01")
+                        .param("internshipEnd", "2026-12-31"))
+                .andExpect(status().is3xxRedirection());
+
+        mockMvc.perform(post("/admin/accounts")
+                        .with(user("admin@example.com").roles("ADMIN"))
+                        .with(csrf())
+                        .param("email", "second-intern@example.com")
+                        .param("displayName", "Second Intern")
+                        .param("role", "INTERN")
+                        .param("studentCode", "  stu-round-2  ")
+                        .param("internshipStart", "2026-08-01")
+                        .param("internshipEnd", "2026-12-31"))
+                .andExpect(status().isOk())
+                .andExpect(view().name("accounts/new"))
+                .andExpect(content().string(org.hamcrest.Matchers.containsString(
+                        "An Intern with this student code already exists")))
+                .andExpect(content().string(org.hamcrest.Matchers.not(
+                        org.hamcrest.Matchers.containsString("this email already exists"))))
+                .andExpect(content().string(org.hamcrest.Matchers.containsString("Second Intern")));
+    }
+
     @Test
     void additionalAdminActivatesAndAuthenticatesWithoutChangingTheFirstAdmin() throws Exception {
         mockMvc.perform(post("/admin/accounts")

src/test/java/com/lab/labtimesheet/feature/integration/controller/SmtpOnboardingWebIntegrationTest.java

@@ -157,7 +157,8 @@ class SmtpOnboardingWebIntegrationTest {
                         .with(user("admin@example.com").roles("ADMIN")))
                 .andReturn().getResponse().getContentAsString();
         String draftId = html.replaceAll("(?s).*name=\"draftId\" value=\"([0-9]+)\".*", "$1");
-        probe.failureMessage = "Connection refused by the configured SMTP server";
+        String rawDiagnostic = "AUTH rejected for smtp-secret-raw-diagnostic";
+        probe.failureMessage = rawDiagnostic;
 
         mockMvc.perform(post("/admin/smtp/test")
                         .with(user("admin@example.com").roles("ADMIN"))
@@ -166,7 +167,9 @@ class SmtpOnboardingWebIntegrationTest {
                 .andExpect(status().isOk())
                 .andExpect(view().name("smtp/form"))
                 .andExpect(content().string(org.hamcrest.Matchers.containsString(
-                        "Connection refused by the configured SMTP server")))
+                        "SMTP test failed. Verify the draft settings and server availability, then try again.")))
+                .andExpect(content().string(org.hamcrest.Matchers.not(
+                        org.hamcrest.Matchers.containsString(rawDiagnostic))))
                 .andExpect(content().string(org.hamcrest.Matchers.not(
                         org.hamcrest.Matchers.containsString("Activate SMTP"))));
     }