Fix TypeScript build error for blog frontmatter fields

[Copilot]

The CI build was failing because blog posts used custom frontmatter fields (date, author, tags) that weren't typed in the fumadocs-mdx schema. Type casts (as any) masked this until TypeScript compilation.

Changes

source.config.ts

• Configure blog schema via docs.schema property with extended frontmatter
• Use z.coerce.string() for date field to handle YAML's auto-parsing to Date objects

source.ts

• Remove as any casts to enable type inference

page.tsx

• Add BlogPostData interface and type assertions for custom fields
• Preserve original page.data.body access for MDX component

// Before: unsafe cast hid the missing schema
export const blog = defineDocs({
  dir: '../../content/blog',
}) as any;

// After: explicit schema configuration
const blogSchema = frontmatterSchema.extend({
  date: z.coerce.string().optional(),
  author: z.string().optional(),
  tags: z.array(z.string()).optional(),
});

export const blog = defineDocs({
  dir: '../../content/blog',
  docs: { schema: blogSchema },
});

Original prompt

引用: https://github.com/objectstack-ai/spec/actions/runs/21161689880/job/60857524435#step:8:1

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Project	Deployment	Review	Updated (UTC)
spec	Ready	Preview, Comment	Jan 20, 2026 7:28am