CC/MCP scheduled tasks silently fire on Opus 5 despite claude-sonnet-5 configured default

Scheduled tasks created via `create_scheduled_task` (CC/MCP surface) have no live `model` field — the model is bound at a server-side pin, not the org/session's configured default (`settings.json` → `claude-sonnet-5`, confirmed correctly set on our side).

Canary evidence (session-metadata read via `get_session`, 2026-07-26, 6 sampled fires):

| Task | Fired (UTC) | Model |
|---|---|---|
| ora-aaos-publish-contracts | 07-25 19:07 | `claude-opus-5[1m]` |
| ora-pm-ledger | 07-25 22:09 | `claude-sonnet-5` |
| ora-health-guard | 07-26 14:58 | `claude-sonnet-5` |
| ora-aaos-expire-leases | 07-26 14:58 | `claude-opus-5[1m]` |
| ora-aaos-publish-contracts | 07-26 15:00 | `claude-opus-5[1m]` |
| ora-override-sweep-dryrun-check | 07-26 15:53 | `claude-opus-5[1m]` |

4 of 6 fires landed on Opus 5, not the configured Sonnet default. Notably the *same task* (`ora-aaos-publish-contracts`) hit Opus 5 on two separate fires, while other tasks with no special configuration landed on Sonnet — indicating the pin is non-deterministic per-session, not a fixed per-task assignment. We first caught this pattern 2026-07-08 (then pinned to `claude-opus-4-8`); the rollout to Opus 5 just reproduced the same gap under a new model id.

**Impact:** routine/low-complexity scheduled automations silently bill at Opus rates with no way to detect it except manual transcript/session-metadata canaries after the fact, and no way to fix it — there is no `model` parameter exposed on `create_scheduled_task` / `update_scheduled_task` to pin the fleet to a chosen tier.

**Ask:** either (a) honor the account/org-level default model for CC/MCP scheduled-task execution, or (b) expose a `model` field on `create_scheduled_task`/`update_scheduled_task` so it can be set explicitly per task, matching how the LAMS/Cowork scheduled-task surface already behaves (model is set at creation and stays put there).

Start by tracing the create_scheduled_task and update_scheduled_task entry points for CC/MCP, then compare their model handling with the LAMS/Cowork scheduled-task surface. Use settings.json and get_session session metadata to understand the configured and observed models. Done means scheduled tasks consistently honor the configured default or expose an explicit model field, with coverage for both creation and updates.

Written by the indexing model from the issue text.