fix(myorg-assistant): add missing GIT_TOKEN to all CronJob pods (deadline-checker, morning-briefing, evening-summary, waiting-followup)

All four CronJobs share the same image + run_job entrypoint and import
Settings(), which requires git_token. Only git-sync and the Deployment
supplied these. Added GIT_REPO_URL/GIT_USERNAME/GIT_TOKEN secret env vars
to the other three CronJobs to prevent the same pydantic ValidationError
crash at import.

myorg-assistant/cronjobs/morning-briefing.yaml

@@ -66,6 +66,21 @@ spec:
                 secretKeyRef:
                   name: myorg-assistant-secret
                   key: WEB_SECRET_KEY
+            - name: GIT_REPO_URL
+              valueFrom:
+                secretKeyRef:
+                  name: myorg-assistant-secret
+                  key: GIT_REPO_URL
+            - name: GIT_USERNAME
+              valueFrom:
+                secretKeyRef:
+                  name: myorg-assistant-secret
+                  key: GIT_USERNAME
+            - name: GIT_TOKEN
+              valueFrom:
+                secretKeyRef:
+                  name: myorg-assistant-secret
+                  key: GIT_TOKEN
             volumeMounts:
             - name: myorg-data
               mountPath: /data/myorg