fix(myorg-assistant): fix ImagePullBackOff on cronjobs — use Gitea registry image

All 5 CronJob manifests (deadline-checker, evening-summary, git-sync,
morning-briefing, waiting-followup) referenced 'myorg-assistant:latest'
—a bare local image name that doesn't exist on any node. The main
Deployment already uses git.rogi.casa/roger/myorg-assistant/myorg-assistant:fcf79bf.

Changes per cronjob:
- image: myorg-assistant:latest → git.rogi.casa/.../myorg-assistant:fcf79bf
- imagePullPolicy: IfNotPresent → Always (match Deployment)
- Add imagePullSecrets: gitea-registry (required for private registry)

This fixes 4 pods stuck in ImagePullBackOff for ~6+ hours.

myorg-assistant/cronjobs/evening-summary.yaml

@@ -22,10 +22,12 @@ spec:
             job: evening-summary
         spec:
           restartPolicy: OnFailure
+          imagePullSecrets:
+          - name: gitea-registry
           containers:
           - name: evening-summary
-            image: myorg-assistant:latest
-            imagePullPolicy: IfNotPresent
+            image: git.rogi.casa/roger/myorg-assistant/myorg-assistant:fcf79bf
+            imagePullPolicy: Always
             command:
             - python
             - run_job.py