feat(upgrade): surface btree_gist NaN reindex warning (#49684)

## 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 — studio counterpart of supabase/platform#37696 (PG 15.19/17.11
release, PSQL-1247).

## What is the current behavior?

The pre-upgrade warnings panel handles `ltree_reindex_required` and
`operator_estimator_gate` only.

## What is the new behavior?

Adds the `btree_gist_nan_reindex` warning (title, description, docs
link) emitted by the eligibility endpoint when a project has btree_gist
indexes on float columns and the upgrade crosses the 15.19/17.11
NaN-handling fix. Non-blocking, same pattern as #47003. `api-v1.d.ts`
union extended to match the platform spec.

## Additional context

Docs anchor targets the section added in #49621 — merge that first (or
together). Refs PSQL-1247.

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

## Summary by CodeRabbit

* **New Features**
* Added an upgrade warning for the `btree_gist_nan_reindex` requirement.
* Included a description and link to relevant documentation for
guidance.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

apps/studio/components/interfaces/Settings/Infrastructure/UpgradeWarnings.tsx

@@ -164,6 +164,8 @@ const getWarningTitle = (warning: ProjectUpgradeEligibilityWarning): string => {
       return 'ltree indexes must be reindexed after this upgrade'
     case 'operator_estimator_gate':
       return 'Custom operators may need attention after this upgrade'
+    case 'btree_gist_nan_reindex':
+      return 'btree_gist indexes on float columns must be reindexed after this upgrade'
   }
 }
 
@@ -175,6 +177,8 @@ const getWarningDescription = (warning: ProjectUpgradeEligibilityWarning): strin
       return 'After upgrading, ltree indexes on this database can return incomplete results until they are rebuilt. Run `REINDEX INDEX CONCURRENTLY` on the affected indexes — this runs online with no downtime.'
     case 'operator_estimator_gate':
       return 'After upgrading, recreating an operator that references a non-built-in selectivity estimator (for example during a restore or branch) requires superuser and may fail. Most projects are not affected.'
+    case 'btree_gist_nan_reindex':
+      return 'After upgrading, btree_gist indexes on float columns can return wrong results for rows containing NaN until they are rebuilt. If those columns may contain NaN values, run `REINDEX INDEX CONCURRENTLY` on the affected indexes — this runs online with no downtime.'
   }
 }
 
@@ -186,6 +190,8 @@ const getWarningLink = (warning: ProjectUpgradeEligibilityWarning): string => {
       return `${DOCS_URL}/guides/platform/upgrading#ltree-indexes-require-reindexing-after-upgrade`
     case 'operator_estimator_gate':
       return `${DOCS_URL}/guides/platform/upgrading#custom-operator-selectivity-estimators`
+    case 'btree_gist_nan_reindex':
+      return `${DOCS_URL}/guides/platform/upgrading#btree_gist-indexes-on-float-columns-require-reindexing-after-upgrade`
   }
 }
 

packages/api-types/types/api-v1.d.ts

@@ -4045,6 +4045,10 @@ export interface components {
             /** @enum {string} */
             type: 'operator_estimator_gate'
           }
+        | {
+            /** @enum {string} */
+            type: 'btree_gist_nan_reindex'
+          }
       )[]
     }
     ProjectUpgradeInitiateResponse: {