Fix meta information

[dfberry]

This pull request updates the metadata and frontmatter of the blog post 2026-07-07-surprises-self-hosting-image-model.md to improve SEO, organization, and consistency. The main changes include adding new metadata fields, updating tag formatting, and ensuring the title and sidebar label are clear and descriptive.

Metadata and SEO improvements:

• Added canonical_url, custom_edit_url, and sidebar_label fields to the frontmatter for better SEO and sidebar organization.
• Updated the tags field to use lowercase and list format for consistency and improved searchability.

Content organization:

• Ensured the title and sidebar_label are clear and descriptive for easier navigation.

Formatting fixes:

• Removed an unnecessary blank line after the keywords section for cleaner formatting.