feat(automation): add daily briefing preset and cron backup scheduling

config/default.yaml

@@ -245,6 +245,20 @@ hooks:
 #         channel: telegram
 #         peer: "123456789"
 #
+#   # Optional built-in morning briefing job (auto-registered as a cron job)
+#   daily_briefing:
+#     enabled: false
+#     name: daily-briefing
+#     schedule: "0 8 * * *"
+#     timezone: America/New_York
+#     output:
+#       channel: telegram
+#       peer: "123456789"
+#     model_tier: fast
+#     prompt: |
+#       Create my daily briefing.
+#       Summarize today's calendar, unread/important email, and top pending tasks.
+#
 #   webhooks:
 #     - name: github-push
 #       secret: "whsec_..."
@@ -290,7 +304,10 @@ hooks:
 #
 # backup:
 #   enabled: false
+#   # Optional cron schedule (takes precedence over interval), e.g. nightly at 2 AM.
+#   schedule: "0 2 * * *"
 #   interval: "24h"
+#   run_on_start: false
 #   local_dir: ~/.local/share/flynn/backups
 #   include_vectors: true
 #   minio: