fix: resolve @groombook/db source in vitest config

Add resolve alias so vitest can resolve @groombook/db from source
TypeScript files without requiring a prior build step. Fixes CI
test failures when dist/ has not been compiled.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

apps/api/vitest.config.ts

@@ -1,6 +1,12 @@
 import { defineConfig } from "vitest/config";
+import path from "path";
 
 export default defineConfig({
+  resolve: {
+    alias: {
+      "@groombook/db": path.resolve(__dirname, "../../packages/db/src/index.ts"),
+    },
+  },
   test: {
     coverage: {
       provider: "v8",