## Context
This is just pulling out the relevant changes from
https://github.com/supabase/supabase/pull/49028 as I might have messed
up the stack while making changes down the PRs 🙏
Builds on the Query Tab in the Explorer UI, adds the source selector
component to run either a database query or a logs query - will
subsequently be looking into have the source selector component in the
QueryCell as well (within notebooks)
<img width="1095" height="594" alt="image"
src="https://github.com/user-attachments/assets/ab6e8d91-aed3-4845-9777-acbd7a3a7cb1"
/>
<img width="1086" height="667" alt="image"
src="https://github.com/user-attachments/assets/75d99063-755d-4ba6-a128-7ddcbbc9f161"
/>
<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit
- **New Features**
- Added query-source selection for Explorer and notebook queries.
- Supports log queries, database selection, and read-replica
connections.
- Added validation for custom log time ranges and retention limits, with
upgrade guidance when applicable.
- Query source choices are saved and restored across sessions.
- Changing sources clears previous results to prevent stale data.
- **Bug Fixes**
- Improved handling of unavailable log querying and missing database
connections.
- Legacy saved queries now fall back safely to the default database
source.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->
