Problem

Plans are special-cased throughout the codebase: PlanGrid groups by topic, PlanCard renders a nested list of plans per topic, and both page routes branch on collection === "plans". This creates a different UX from every other collection and makes pagination incorrect — PAGE_SIZE operates on individual plans but the display groups them, so a page of 30 plans might show only 5 topic cards.

Design

1. Schema changes

Remove plan-specific fields planType and topic. Add a generic subcategory field available to all collections.

Before:

planType: z.enum(["design", "implementation"]).optional(),
topic: z.string().optional(),

After:

subcategory: z.string().optional(),

2. Frontmatter migration (97 plan files)

For each plan .md file:

  • Remove planType field; add its value (design or implementation) to the tags array
  • Rename topic → subcategory

Before:

planType: implementation
topic: collection-pagination
category: layout
tags: []

After:

subcategory: collection-pagination
category: layout
tags: [implementation]

3. Card display

  • Plans switch from cardVariant: "plan" to cardVariant: "compact" (same as recipes)
  • CompactCard gains an optional subcategory line between category and date
  • planType values now appear naturally via CardTags since they’re in the tags array

4. Remove plan-specific code

  • Delete PlanGrid.astro
  • Delete PlanCard.astro
  • Remove collection === "plans" branches from [collection]/[...page].astro and [collection]/[category]/[...page].astro
  • Remove "plan" from CardVariant type
  • Remove plan fallback line from Card.astro

5. NavItem type

  • Add optional subcategory: string field
  • Remove topic and planType fields

6. Future work (not in this change)

  • Subcategory filter UI on collection pages
  • Add subcategory to other collections