Mirror the stamping + read-precedence work from TRI-9073 in the
ai-chat-feature-branch-only routes:
- Playground action: stamp `streamBasinName` from
`environment.organization.streamBasinName` on Session.upsert.
- Playground SSE / append routes: pass `{ session }` to
`getRealtimeStreamInstance` so basin resolves via session row.
- Dashboard run-stream / run-input / run-session SSE routes (the
dashboard-auth counterparts to the public /realtime/v1/* routes):
same plumbing.
These files only exist on this branch (they were added by the
chat-agent / Sessions PRs), so the plumbing rides along here rather
than on the basin migration branch.
Refs TRI-9073.
Eric Allam
785d0153e8