fix: use PostgreSQL service container in CI instead of Testcontainers

Testcontainers can't network properly on TrueNAS act-runner (host network vs bridge). Added postgres:16-alpine service container to CI workflow and made AbstractIntegrationTest conditionally skip Testcontainers when CI_POSTGRES_URL env var is present.

cannamanage-api/src/test/java/de/cannamanage/api/integration/AbstractIntegrationTest.java

@@ -42,16 +42,31 @@ import java.util.UUID;
 public abstract class AbstractIntegrationTest {
 
     @Container
-    static PostgreSQLContainer<?> postgres = new PostgreSQLContainer<>("postgres:16-alpine")
-            .withDatabaseName("cannamanage_test")
-            .withUsername("test")
-            .withPassword("test");
+    static PostgreSQLContainer<?> postgres = shouldUseTestcontainers()
+            ? new PostgreSQLContainer<>("postgres:16-alpine")
+                .withDatabaseName("cannamanage_test")
+                .withUsername("test")
+                .withPassword("test")
+            : null;
 
     @DynamicPropertySource
     static void configureProperties(DynamicPropertyRegistry registry) {
-        registry.add("spring.datasource.url", postgres::getJdbcUrl);
-        registry.add("spring.datasource.username", postgres::getUsername);
-        registry.add("spring.datasource.password", postgres::getPassword);
+        if (postgres != null) {
+            registry.add("spring.datasource.url", postgres::getJdbcUrl);
+            registry.add("spring.datasource.username", postgres::getUsername);
+            registry.add("spring.datasource.password", postgres::getPassword);
+        } else {
+            registry.add("spring.datasource.url", () -> System.getenv("CI_POSTGRES_URL"));
+            registry.add("spring.datasource.username", () -> System.getenv("CI_POSTGRES_USER"));
+            registry.add("spring.datasource.password", () -> System.getenv("CI_POSTGRES_PASSWORD"));
+        }
+    }
+
+    /**
+     * Use Testcontainers locally; skip when CI provides PostgreSQL via service container.
+     */
+    private static boolean shouldUseTestcontainers() {
+        return System.getenv("CI_POSTGRES_URL") == null;
     }
 
     @LocalServerPort