fix dev failing tests (#955)

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<!-- RECURSEML_SUMMARY:START -->
## High-level PR Summary
This PR fixes database schema issues related to Prisma migrations by
setting the correct `search_path` before applying auto-migrations and
removing the `SchemaMigration` table from the CI workflow to ensure
proper schema comparison during migration checks.

⏱️ Estimated Review Time: 5-15 minutes

<details>
<summary>💡 Review Order Suggestion</summary>

| Order | File Path |
|-------|-----------|
| 1 | `apps/backend/src/auto-migrations/index.tsx` |
| 2 | `.github/workflows/check-prisma-migrations.yaml` |
</details>



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----

> [!IMPORTANT]
> Fixes Prisma migration schema issues and a string concatenation error
in `getUserInfo`.
> 
>   - **Database Schema**:
> - Removes `SchemaMigration` table in
`.github/workflows/check-prisma-migrations.yaml` to ensure correct
schema comparison.
> - Sets `STACK_SEED_MODE` to `'true'` in `seed()` in `seed.ts` for
consistent seeding behavior.
>   - **Bug Fix**:
> - Fixes string concatenation error in `getUserInfo` in
`myFunctions.ts` by using `+` instead of `obj.displayName`.
> 
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<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->

## Summary by CodeRabbit

* **Bug Fixes**
* Corrected user info message to properly display the user’s name in the
example app.

* **Chores**
* CI workflow now clears auto-generated migration metadata before
comparing schema changes to reduce false positives.
* Seeding now explicitly sets a seed-mode environment flag and no longer
auto-executes on direct invocation, enabling more controlled runs.

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

.github/workflows/check-prisma-migrations.yaml

@@ -59,5 +59,12 @@ jobs:
       - name: Initialize database
         run: pnpm run db:init
 
+      - name: Remove auto-migration metadata
+        run: |
+          cd apps/backend
+          pnpm run prisma db execute --url postgres://postgres:PASSWORD-PLACEHOLDER--uqfEC1hmmv@localhost:5432/stackframe --stdin <<'SQL'
+          DROP TABLE IF EXISTS "SchemaMigration";
+          SQL
+
       - name: Check for differences in Prisma schema and current DB
         run: cd apps/backend && pnpm run prisma migrate diff --from-url postgres://postgres:PASSWORD-PLACEHOLDER--uqfEC1hmmv@localhost:5432/stackframe --to-schema-datamodel ./prisma/schema.prisma --shadow-database-url postgres://postgres:PASSWORD-PLACEHOLDER--uqfEC1hmmv@localhost:5432/shadow_db --exit-code