feat(storage): prefill expiration policy inputs with 30 days / 10 versions

Create modal: expiration inputs default to 30 days and 10 versions
instead of empty, so toggling versioning on surfaces a policy that's
ready to save. Clearing a field still removes that condition from the
policy.

Edit modal: same defaults, but only when the bucket has never had
versioning enabled — buckets already versioned keep their existing
values (including explicit null == "no limit on this condition"), so
the modal never silently retro-adds a condition the user removed.

apps/studio/components/interfaces/Storage/BucketDataProtectionFields.tsx

@@ -96,8 +96,9 @@ export const BucketDataProtectionFields = ({
   // Turning versioning off never deletes anything by itself — a bucket that's
   // ever had it enabled can only be suspended, not returned to a plain
   // "disabled" state, so nothing needs a destructive confirmation here.
-  // Both expiration fields default to empty (no limit) — the user opts in to
-  // each condition deliberately rather than receiving prefilled defaults.
+  // The two expiration fields come prefilled with sensible starter values
+  // (see CreateBucketModal / EditBucketModal defaults) — clearing a field
+  // removes that condition from the policy.
   const handleVersioningToggle = (checked: boolean, onChange: (value: boolean) => void) => {
     onChange(checked)
   }

apps/studio/components/interfaces/Storage/CreateBucketModal.tsx

@@ -130,8 +130,11 @@ export const CreateBucketModal = ({ open, onOpenChange }: CreateBucketModalProps
       formatted_size_limit: undefined,
       allowed_mime_types: '',
       enable_versioning: false,
-      version_expiry_days: '',
-      max_noncurrent_versions: '',
+      // Prefill sensible defaults so the inputs aren't blank the moment
+      // versioning is toggled on. A no-policy bucket has to be an explicit
+      // opt-out — clear the field to remove that condition.
+      version_expiry_days: 30,
+      max_noncurrent_versions: 10,
       expiration_mode: 'and',
     },
   })

apps/studio/components/interfaces/Storage/EditBucketModal.tsx

@@ -126,6 +126,20 @@ export const EditBucketModal = ({ visible, bucket, onClose }: EditBucketModalPro
     },
   })
 
+  // Prefill the two expiration inputs with sensible starter values when the
+  // bucket has never had versioning turned on — so toggling versioning on
+  // for the first time surfaces a policy ready to save, matching the create
+  // form's defaults. If versioning is already on (or has been in the past)
+  // respect the bucket's own values, including `null` which means the user
+  // explicitly opted out of that particular condition.
+  const hasEverBeenVersioned = bucketProtection.versioning !== 'disabled'
+  const defaultVersionExpiryDays = hasEverBeenVersioned
+    ? (bucketProtection.versionExpiryDays ?? ('' as const))
+    : 30
+  const defaultMaxNoncurrentVersions = hasEverBeenVersioned
+    ? (bucketProtection.maxNoncurrentVersions ?? ('' as const))
+    : 10
+
   const defaultValues = {
     name: bucket?.name ?? '',
     public: bucket?.public,
@@ -133,8 +147,8 @@ export const EditBucketModal = ({ visible, bucket, onClose }: EditBucketModalPro
     formatted_size_limit: bucket?.file_size_limit ? (fileSizeLimit ?? 0) : undefined,
     allowed_mime_types: (bucket?.allowed_mime_types ?? []).join(', '),
     enable_versioning: !!planLimits && bucketProtection.versioning === 'enabled',
-    version_expiry_days: bucketProtection.versionExpiryDays ?? ('' as const),
-    max_noncurrent_versions: bucketProtection.maxNoncurrentVersions ?? ('' as const),
+    version_expiry_days: defaultVersionExpiryDays,
+    max_noncurrent_versions: defaultMaxNoncurrentVersions,
     expiration_mode: bucketProtection.expirationMode,
   }