Fix React projects example

[copyleftproducts]

🎯 Changes

Fix the React projects example, which is currently broken.
-use correct property names for users.createdAt and users.updatedAt
-add migration for missing projects.updated_at and todos.updated_at columns -

✅ Checklist

• [*] I have tested this code locally with pnpm test.

Running pnpm test locally gives two errors, both in main and for this PR:

FAIL @tanstack/db-ivm tests/operators/topK.test.ts > Operators > TopK operation > incremental update - complex scenario with multiple changes

FAIL @tanstack/db-ivm tests/operators/topKWithIndex.test.ts > Operators > TopKWithIndex operation > incremental update with offset - items moving in and out of window

🚀 Release Impact

• This change affects published code, and I have generated a changeset.
• This change is docs/CI/dev-only (no release).

Flagging this as draft due to the pnpm test errors I observe. I don't see how fixing a broken example project could influence the tests, so I assume it's something environment related.

[changeset-bot]

⚠️ No Changeset found

Latest commit: aa5af7e

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