feat(cron): add --model flag to cron add/edit commands

Expose the existing model override capability via CLI flags:
- Add --model to cron add and cron edit commands
- Document model and thinking overrides in cron-jobs.md
- Add CLI example showing model/thinking usage

The backend already supported model in agentTurn payloads;
this change exposes it through the CLI interface.

docs/automation/cron-jobs.md

@@ -61,9 +61,19 @@ Key behaviors:
 - `wakeMode: "now"` triggers an immediate heartbeat after posting the summary.
 - If `payload.deliver: true`, output is delivered to a provider; otherwise it stays internal.
 
-Use isolated jobs for noisy, frequent, or “background chores” that shouldn’t spam
+Use isolated jobs for noisy, frequent, or "background chores" that shouldn't spam
 your main chat history.
 
+### Model and thinking overrides
+Isolated jobs (`agentTurn`) can override the model and thinking level:
+- `model`: Provider/model string (e.g., `anthropic/claude-sonnet-4-20250514`) or alias (e.g., `opus`)
+- `thinking`: Thinking level (`off`, `minimal`, `low`, `medium`, `high`)
+
+Resolution priority:
+1. Job payload override (highest)
+2. Hook-specific defaults (e.g., `hooks.gmail.model`)
+3. Agent config default
+
 ### Delivery (provider + target)
 Isolated jobs can deliver output to a provider. The job payload can specify:
 - `provider`: `whatsapp` / `telegram` / `discord` / `slack` / `signal` / `imessage` / `last`
@@ -142,6 +152,21 @@ clawdbot cron add \
   --to "-1001234567890:topic:123"
 ```
 
+Isolated job with model and thinking override:
+```bash
+clawdbot cron add \
+  --name "Deep analysis" \
+  --cron "0 6 * * 1" \
+  --tz "America/Los_Angeles" \
+  --session isolated \
+  --message "Weekly deep analysis of project progress." \
+  --model "opus" \
+  --thinking high \
+  --deliver \
+  --provider whatsapp \
+  --to "+15551234567"
+```
+
 Manual run (debug):
 ```bash
 clawdbot cron run <jobId> --force