feat(02-04): populate diagram_content_hash during ingestion and fix test stability

- Inject DiagramRepository into ClickHouseExecutionRepository for hash lookup
- Replace empty string placeholder with actual SHA-256 diagram hash in insertBatch
- Add Surefire/Failsafe forkCount=1 reuseForks=false for classloader isolation
- Add failsafe-plugin integration-test/verify goals for IT execution
- Create DiagramLinkingIT with positive (hash populated) and negative (empty fallback) cases
- Fix flaky awaitility assertions with ignoreExceptions for EmptyResultDataAccess
- Increase IngestionSchemaIT timeouts to 30s for reliable batch flush waits
- Adjust SearchControllerIT pagination assertion to match correct seed data count

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

cameleer3-server-app/pom.xml

@@ -90,6 +90,30 @@
                 <groupId>org.springframework.boot</groupId>
                 <artifactId>spring-boot-maven-plugin</artifactId>
             </plugin>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-surefire-plugin</artifactId>
+                <configuration>
+                    <forkCount>1</forkCount>
+                    <reuseForks>false</reuseForks>
+                </configuration>
+            </plugin>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-failsafe-plugin</artifactId>
+                <configuration>
+                    <forkCount>1</forkCount>
+                    <reuseForks>false</reuseForks>
+                </configuration>
+                <executions>
+                    <execution>
+                        <goals>
+                            <goal>integration-test</goal>
+                            <goal>verify</goal>
+                        </goals>
+                    </execution>
+                </executions>
+            </plugin>
         </plugins>
     </build>
 </project>

cameleer3-server-app/src/main/java/com/cameleer3/server/app/storage/ClickHouseExecutionRepository.java

@@ -4,6 +4,7 @@ import com.cameleer3.common.model.ExchangeSnapshot;
 import com.cameleer3.common.model.ProcessorExecution;
 import com.cameleer3.common.model.RouteExecution;
 import com.cameleer3.server.core.detail.RawExecutionRow;
+import com.cameleer3.server.core.storage.DiagramRepository;
 import com.cameleer3.server.core.storage.ExecutionRepository;
 import com.fasterxml.jackson.core.JsonProcessingException;
 import com.fasterxml.jackson.databind.ObjectMapper;
@@ -53,9 +54,11 @@ public class ClickHouseExecutionRepository implements ExecutionRepository {
             """;
 
     private final JdbcTemplate jdbcTemplate;
+    private final DiagramRepository diagramRepository;
 
-    public ClickHouseExecutionRepository(JdbcTemplate jdbcTemplate) {
+    public ClickHouseExecutionRepository(JdbcTemplate jdbcTemplate, DiagramRepository diagramRepository) {
         this.jdbcTemplate = jdbcTemplate;
+        this.diagramRepository = diagramRepository;
     }
 
     @Override
@@ -138,7 +141,10 @@ public class ClickHouseExecutionRepository implements ExecutionRepository {
                 ps.setObject(col++, inputHeaders);                  // processor_input_headers
                 ps.setObject(col++, outputHeaders);                 // processor_output_headers
                 ps.setObject(col++, diagramNodeIds);                // processor_diagram_node_ids
-                ps.setString(col++, "");                            // diagram_content_hash (wired later)
+                String diagramHash = diagramRepository
+                        .findContentHashForRoute(exec.getRouteId(), "")
+                        .orElse("");
+                ps.setString(col++, diagramHash);                   // diagram_content_hash
             }
 
             @Override

cameleer3-server-app/src/test/java/com/cameleer3/server/app/controller/SearchControllerIT.java

@@ -327,12 +327,12 @@ class SearchControllerIT extends AbstractClickHouseIT {
 
     @Test
     void pagination_worksCorrectly() throws Exception {
-        // First, get total count of COMPLETED executions (8 from our seed data,
-        // but may include data from other test classes)
+        // First, get total count of COMPLETED executions (7 from our seed data:
+        // exec 1 + execs 5-10; execs 2,4 are FAILED, exec 3 is RUNNING)
         ResponseEntity<String> countResponse = searchGet("?status=COMPLETED&limit=1");
         JsonNode countBody = objectMapper.readTree(countResponse.getBody());
         long totalCompleted = countBody.get("total").asLong();
-        assertThat(totalCompleted).isGreaterThanOrEqualTo(8);
+        assertThat(totalCompleted).isGreaterThanOrEqualTo(7);
 
         // Now test pagination with offset=2, limit=3
         ResponseEntity<String> response = searchPost("""

cameleer3-server-app/src/test/java/com/cameleer3/server/app/storage/DiagramLinkingIT.java

@@ -91,7 +91,7 @@ class DiagramLinkingIT extends AbstractClickHouseIT {
         assertThat(execResponse.getStatusCode()).isEqualTo(HttpStatus.ACCEPTED);
 
         // 4. Verify diagram_content_hash is a non-empty SHA-256 hash (64 hex chars)
-        await().atMost(10, SECONDS).untilAsserted(() -> {
+        await().atMost(10, SECONDS).ignoreExceptions().untilAsserted(() -> {
             String hash = jdbcTemplate.queryForObject(
                     "SELECT diagram_content_hash FROM route_executions WHERE route_id = 'diagram-link-route'",
                     String.class);
@@ -140,7 +140,7 @@ class DiagramLinkingIT extends AbstractClickHouseIT {
         assertThat(response.getStatusCode()).isEqualTo(HttpStatus.ACCEPTED);
 
         // Verify diagram_content_hash is empty string (graceful fallback)
-        await().atMost(10, SECONDS).untilAsserted(() -> {
+        await().atMost(10, SECONDS).ignoreExceptions().untilAsserted(() -> {
             String hash = jdbcTemplate.queryForObject(
                     "SELECT diagram_content_hash FROM route_executions WHERE route_id = 'no-diagram-route'",
                     String.class);

cameleer3-server-app/src/test/java/com/cameleer3/server/app/storage/IngestionSchemaIT.java

@@ -84,7 +84,7 @@ class IngestionSchemaIT extends AbstractClickHouseIT {
 
         postExecution(json);
 
-        await().atMost(10, SECONDS).untilAsserted(() -> {
+        await().atMost(30, SECONDS).ignoreExceptions().untilAsserted(() -> {
             // Use individual typed queries to avoid ClickHouse Array cast issues
             var depths = queryArray(
                     "SELECT processor_depths FROM route_executions WHERE route_id = 'schema-test-tree'");
@@ -160,7 +160,7 @@ class IngestionSchemaIT extends AbstractClickHouseIT {
 
         postExecution(json);
 
-        await().atMost(10, SECONDS).untilAsserted(() -> {
+        await().atMost(30, SECONDS).ignoreExceptions().untilAsserted(() -> {
             // Bodies should contain all sources
             String bodies = jdbcTemplate.queryForObject(
                     "SELECT exchange_bodies FROM route_executions WHERE route_id = 'schema-test-bodies'",
@@ -206,7 +206,7 @@ class IngestionSchemaIT extends AbstractClickHouseIT {
 
         postExecution(json);
 
-        await().atMost(10, SECONDS).untilAsserted(() -> {
+        await().atMost(30, SECONDS).ignoreExceptions().untilAsserted(() -> {
             // Empty but not null
             String bodies = jdbcTemplate.queryForObject(
                     "SELECT exchange_bodies FROM route_executions WHERE route_id = 'schema-test-null-snap'",