fix(sql-orm-client): replace bare as casts in resolveThrough with castAs

The 5 bare `as` casts in `resolveThrough` (parentColumns/childColumns in
the Set spread, and all three *Columns in the return object) were
declarative widenings from `unknown[]` to `readonly string[]`.  Replace
all five with `castAs<readonly string[]>(…)` from `@prisma-next/utils/casts`
per the no-bare-casts rule.

No behaviour change.  lint:casts delta: -1.

Signed-off-by: Alexey Orlenko's AI Agent <robot@aqrln.net>

Author: tensordreams

packages/3-extensions/sql-orm-client/src/collection-contract.ts

@@ -5,6 +5,7 @@ import {
   contractModels,
 } from '@prisma-next/contract/types';
 import type { SqlStorage, StorageTable } from '@prisma-next/sql-contract/types';
+import { castAs } from '@prisma-next/utils/casts';
 import type { RelationCardinalityTag } from './types';
 
 type ModelStorageFields = Record<string, { column?: string }>;
@@ -271,8 +272,8 @@ function resolveThrough(
   }
 
   const fkColumnSet = new Set<string>([
-    ...(parentColumns as string[]),
-    ...(childColumns as string[]),
+    ...castAs<readonly string[]>(parentColumns),
+    ...castAs<readonly string[]>(childColumns),
   ]);
   const junctionTable = unboundTable(contract, table);
   const requiredPayloadColumns: string[] = [];
@@ -286,9 +287,9 @@ function resolveThrough(
 
   return {
     table,
-    parentColumns: parentColumns as readonly string[],
-    childColumns: childColumns as readonly string[],
-    targetColumns: targetColumns as readonly string[],
+    parentColumns: castAs<readonly string[]>(parentColumns),
+    childColumns: castAs<readonly string[]>(childColumns),
+    targetColumns: castAs<readonly string[]>(targetColumns),
     requiredPayloadColumns,
   };
 }