Bug

openclaw cron edit --model has no effect when the cron payload uses the text field instead of message.

When kind is not explicitly set, coercePayload() infers systemEvent from the presence of text, then strips all agentTurn-only fields including model. The model override is silently discarded.

This was reported in openclaw#28905 (closed as stale) — this PR provides the root-cause fix.

Fix

In coercePayload(), when text is present alongside agentTurn-only fields (detected by the existing hasAgentTurnPayloadHint()), infer agentTurn and promote text → message instead of inferring systemEvent.

Before

payload: { text: "Run sync", model: "anthropic/claude-sonnet-4-6" }
→ kind: "systemEvent" → model deleted → runs on system default (haiku)

After

payload: { text: "Run sync", model: "anthropic/claude-sonnet-4-6" }
→ kind: "agentTurn", message: "Run sync", model preserved → runs on sonnet

Test plan

• Added test for normalizeCronJobCreate with text + model → verifies promotion to agentTurn
• Added test for normalizeCronJobPatch with text + model → verifies promotion to agentTurn
• Existing test for explicit kind: "systemEvent" + model → still prunes model (no behavior change)
• All 53 cron normalize tests pass
• pnpm check passes

Closes openclaw#28905