Add the Blog Summary Card template (blog-summary-card) #61

Part of #5. A card-style blog preview with a reading-time pill.

Idea
A white card with rounded corners and a soft shadow floats on a light background. The left 38% of the card is a "cover" panel filled with an accent gradient, showing the category name in large type. The right side has a category pill, the title, a two-line excerpt, and a footer with an initials circle for the author, "Author · Date", and a "6 min read" pill.

Template details

• File: src/templates/blog/summary-card.ts, id blog-summary-card
• Fields: commonFields.title, commonFields.description, commonFields.author, commonFields.date, commonFields.category, readTime (text, default "6 min read"), commonFields.siteName, { ...commonFields.bgColor, defaultValue: '#F4F1EC' }, commonFields.accentColor, { ...commonFields.textColor, defaultValue: '#1F2937' }

Where to look

• Closest reference: src/templates/blog/minimal-light.ts (light palette), src/templates/ecommerce/product-card.ts (card with an image area)

Acceptance criteria

• Excerpt is truncated so it never pushes the footer off the card
• Author initials are computed from the author name; the circle is hidden when author is empty
• Re-exported in src/templates/blog/index.ts and registered in the Blog block of src/templates/registry.ts
• Meets the shared template checklist in Add new card-style OG image templates #5

One template per contributor at a time, so more people get a chance.

Want to work on this? Comment below and I'll assign it to you. Please take one issue at a time, branch off dev, and open your PR against dev with Closes #<this issue number>.