feat: add container log service with ClickHouse storage and log API

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

src/test/java/net/siegeln/cameleer/saas/log/ContainerLogServiceTest.java

@@ -0,0 +1,20 @@
+package net.siegeln.cameleer.saas.log;
+
+import org.junit.jupiter.api.Test;
+
+import java.util.concurrent.ConcurrentLinkedQueue;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+class ContainerLogServiceTest {
+
+    @Test
+    void buffer_shouldAccumulateEntries() {
+        var buffer = new ConcurrentLinkedQueue<String>();
+        buffer.add("entry1");
+        buffer.add("entry2");
+        assertEquals(2, buffer.size());
+        assertEquals("entry1", buffer.poll());
+        assertEquals(1, buffer.size());
+    }
+}