feat(deploy): stream live build logs in build progress modal

Show real-time kaniko/init-container build output inside the build
progress modal during the building/deploying phases, alongside the
existing percentage. The build-logs endpoint now returns live pod logs
while a build is in progress (falling back to the persisted log once
finished), and the modal polls it every 2s with auto-scroll. Minimize
behaviour is unchanged.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

backend/src/build/build.service.ts

@@ -1727,6 +1727,24 @@ CMD ["sh", "-c", "DLL=$(find . -maxdepth 1 -name '*.dll' ! -name '*.deps.dll' !
     throw new Error(`Build job ${jobName} timed out after ${timeoutSeconds}s\nLogs:\n${logs}`);
   }
 
+  /**
+   * Live build logs for an in-progress build, read straight from the running
+   * build pod (init + kaniko containers). Returns null when there is no active
+   * build session for this deployment (e.g. build already finished/cleaned up),
+   * so callers can fall back to the persisted build log.
+   */
+  async getLiveBuildLog(deploymentId: string): Promise<string | null> {
+    const session = this.activeBuilds.get(deploymentId);
+    if (!session?.coreApi || !session.namespace || !session.buildPodName) {
+      return null;
+    }
+    try {
+      return await this.getBuildLogs(session.coreApi, session.buildPodName, session.namespace);
+    } catch {
+      return null;
+    }
+  }
+
   private async getBuildLogs(coreApi: k8s.CoreV1Api, jobName: string, namespace: string): Promise<string> {
     try {
       const pods = await coreApi.listNamespacedPod({