fix: resolve aliases before transpiling for rewriteRelativeImportExtensions

[ryanatkn]

This swaps the order of TypeScript transpilation and alias resolution in @sveltejs/package to address the problem described in #13044. TypeScript sees aliases like $lib/ as bare imports and does not apply rewriteRelativeImportExtensions, and resolving aliases first seems like the correct fix. For more see microsoft/TypeScript#61991 (comment)

Before, this code:

import { helper } from '$lib/helper.ts';

Generates this despite rewriteRelativeImportExtensions: true:

import { helper } from './helper.ts';

Now it's correctly:

import { helper } from "./helper.js";

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