fix: start fresh cron sessions each run

docs/automation/cron-jobs.md

@@ -78,6 +78,7 @@ Isolated jobs run a dedicated agent turn in session `cron:<jobId>`.
 
 Key behaviors:
 - Prompt is prefixed with `[cron:<jobId> <job name>]` for traceability.
+- Each run starts a **fresh session id** (no prior conversation carry-over).
 - A summary is posted to the main session (prefix `Cron`, configurable).
 - `wakeMode: "now"` triggers an immediate heartbeat after posting the summary.
 - If `payload.deliver: true`, output is delivered to a channel; otherwise it stays internal.

docs/concepts/session.md

@@ -57,6 +57,7 @@ the workspace is writable. See [Memory](/concepts/memory) and
 - Idle expiry: `session.idleMinutes` (default 60). After the timeout a new `sessionId` is minted on the next message.
 - Reset triggers: exact `/new` or `/reset` (plus any extras in `resetTriggers`) start a fresh session id and pass the remainder of the message through. If `/new` or `/reset` is sent alone, Clawdbot runs a short “hello” greeting turn to confirm the reset.
 - Manual reset: delete specific keys from the store or remove the JSONL transcript; the next message recreates them.
+- Isolated cron jobs always mint a fresh `sessionId` per run (no idle reuse).
 
 ## Send policy (optional)
 Block delivery for specific session types without listing individual ids.