v1.41.0
Late-bound connection refs in flow action steps. Re-auth no longer breaks flows.
```json
"connection": { "platform": "gmail" } // single account
"connection": { "platform": "gmail", "tag": "work@example.com" } // multi-account
```
Resolution runs at flow-execute time. The connection list is fetched once per flow run and cached on the flow context — a many-step flow does ONE `listConnections` round-trip regardless of step count. Selectors work inside the ref's `tag` field for multi-tenant flows.
Backwards compatible: literal `connectionKey` still works.
Companion to v1.40.0 (sync). #121