feat: govern autonomous campaign delivery schedules

README.md

@@ -59,6 +59,20 @@ Files, Mail, Distribution Lists, Templates, Postbox, and Calendar are optional m
 
 Hybrid delivery never treats an opt-in as an implicit duplicate-send instruction. The Campaign author selects one primary route per recipient and may select a supported fallback. A fallback runs only after the first channel rejects before acceptance; accepted or outcome-unknown effects stop cross-channel retry. Printable output is generated once during build, optionally persisted through Files, reviewed with the exact Campaign version, and accepted idempotently per recipient job during delivery.
 
+Recurring schedules have two immutable modes. Manual mode remains the default
+and prepares independent drafts without Mail. Autonomous mode is explicit and
+Mail-only: it seals an already built and explicitly approved execution snapshot,
+rechecks approval, policy, credential/transport revision, live SMTP health,
+recipient and attachment evidence before each occurrence, and submits one
+Mail-owned durable command per frozen message. Occurrence-scoped idempotency is
+allocated before delivery. Accepted and outcome-unknown effects are never
+retried automatically; uncertain or systemic failures pause the schedule,
+notify its accountable operator, and retain non-secret recovery evidence.
+Generated EML retention excludes source versions while an autonomous schedule
+has a remaining occurrence, including while it is paused; once the schedule
+finishes, already accepted Mail commands retain their own encrypted payload and
+evidence under Mail policy.
+
 Public campaign, version, job, and report responses expose business data and
 delivery evidence, but never process-local paths, storage-backend keys, or
 worker claim tokens. Operational troubleshooting uses the dedicated job