Fix seeding errors in exampless/usecase-blog

[envsecure]

Description

This PR fixes the seeding errors in the usecase-blog example reported in #9782.

The issues were:

1. The Post schema was missing status and publishDate fields which are present in the example data.
2. The content field (Document type) was receiving a raw string from the example data, causing a GraphQL error.
3. Lack of safety checks when connecting authors during seeding.

Changes

• Updated examples/usecase-blog/schema.ts to include status and publishDate fields.
• Added select to the imported fields in schema.ts.
• Updated examples/usecase-blog/seed-data.ts to transform the raw content string into a valid Document structure [{ type: 'paragraph', children: [{ text: content }] }].
• Added a check in seed-data.ts to skip posts if the author is not found, preventing crashes.

Verification

I have manually verified the schema and seed logic changes. Since this is a fix for an example's seed script, it ensures a better onboarding experience for new users.

Resolves #9782

[envsecure]

I have updated the branch with a fix for the potential TypeScript errors in seed-data.ts.

Key changes:

1. Added null checks for authorsList[0] to satisfy strict nullability checks.
2. Renamed the shadowed authors variable to authorsList to avoid confusion.
3. Explicitly destructured author from post to ensure it doesn't conflict with the relationship field.

These changes should resolve the "Types" CI check failure.