feat(studio): clarify quick query as temporary space (#49695)

## I have read the
[CONTRIBUTING.md](https://github.com/supabase/supabase/blob/master/CONTRIBUTING.md)
file.

YES

## What kind of change does this PR introduce?

Feature

## What is the current behavior?

Standalone queries in the Explorer "Quick Query" surface have editable
titles (defaulting to "Untitled query") without clear indication that
they are temporary and not saved, similar to the old SQL Editor snippet
model.

## What is the new behavior?

The Quick Query tab now clearly indicates that standalone queries are
temporary. The title is no longer editable and displays "Temporary space
for one-off queries" as static muted italic text. The default query name
has been changed from "Untitled query" to "Quick query" for clarity.

## Additional context

Resolves FE-4297. Notebook cells (variant === 'embedded') remain
unchanged with editable titles.

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

* **UI Improvements**
* Renamed new one-off queries from **“Quick query”** to **“Run SQL”**
when no title is provided.
* Updated viewport query editor toolbars to display the fixed **“Run
SQL”** label.
  * Preserved editable titles for embedded query editors.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

apps/studio/components/interfaces/Explorer/ExplorerQueryTab.tsx

@@ -189,7 +189,7 @@ export const ExplorerQueryTab = () => {
       roleImpersonationState={roleImpersonationState}
       onTitleChange={(value) => {
         persistTab()
-        const name = value.trim() || 'Untitled query'
+        const name = value.trim() || 'Run SQL'
         explorerQueryState.updateDraft({ id, name })
         tabs.updateTab(createTabId('query', { id }), { label: name })
       }}

apps/studio/components/interfaces/Explorer/QueryEditor/index.tsx

@@ -395,7 +395,13 @@ export const QueryEditor = forwardRef<QueryEditorHandle, QueryEditorProps>(funct
           <ExplorerToolbarIcon>
             <CodeSquare size={16} strokeWidth={2} />
           </ExplorerToolbarIcon>
-          <ExplorerToolbarTitle onSaveTitle={onTitleChange}>{title}</ExplorerToolbarTitle>
+          {variant === 'viewport' ? (
+            <ExplorerToolbarTitle className="text-muted text-xs italic">
+              Run SQL
+            </ExplorerToolbarTitle>
+          ) : (
+            <ExplorerToolbarTitle onSaveTitle={onTitleChange}>{title}</ExplorerToolbarTitle>
+          )}
           <ExplorerToolbarActions>
             {onSourceChange && (
               <QuerySourceMenu

apps/studio/state/explorer-query.ts

@@ -237,7 +237,7 @@ export const createExplorerQueryState = (storage: StorageLike = safeLocalStorage
     createDraft: ({
       id,
       projectRef,
-      name = 'Untitled query',
+      name = 'Run SQL',
       sql = '',
       source = createDefaultSourceBinding('database'),
       rowLimit = DEFAULT_CELL_ROW_LIMIT,