I have refactored the SQL Explorer functionality into its own blueprint (routes/sql_explorer.py) with a /sql URL prefix. This involved moving the relevant routes from app.py, registering the new blueprint, removing the old routes, updating url_for calls in the templates, and documenting the change in the changelog.

Here is a conventional commit message summarizing the changes:

```
feat: Refactor SQL Explorer into blueprint

- Moved SQL Explorer routes (view explorer, save/load/execute/delete queries, view schema, plot queries) from `app.py` into a new blueprint at `routes/sql_explorer.py`.
- Added `/sql` URL prefix to the blueprint.
- Registered the new `sql_explorer_bp` blueprint in `app.py`.
- Removed the original SQL Explorer route definitions from `app.py`.
- Updated `url_for` calls in relevant templates (`sql_explorer.html`, `partials/sql_explorer/sql_query.html`, `base.html`) to reference the new blueprint endpoints (e.g., `sql_explorer.sql_explorer`).
- Updated `templates/changelog/changelog.html` to document this refactoring.
```

templates/sql_explorer.html

@@ -9,7 +9,7 @@
         </div>
     </div>
 
-    <div hx-get="{{ url_for('sql_schema') }}" hx-trigger="load"></div>
+    <div hx-get="{{ url_for('sql_explorer.sql_schema') }}" hx-trigger="load"></div>
 
     {{ render_partial('partials/sql_explorer/sql_query.html', saved_queries=saved_queries) }}