improve: bake design guidelines directly into prompts

Instead of requiring a plugin, prompts 01 and 02 now include
specific design instructions (warm palette, typography, spacing)
that produce premium-looking output by default.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

prompts/02-add-categories.md

@@ -6,15 +6,29 @@ Copy and paste this into Claude Code:
 
 Add color-coded categories to the todo app. Requirements:
 
-- Four categories: Work (blue #5B9FD6), Personal (green #4DB8A4), Health (orange #E87020), Learning (purple #A87BDB)
+**Functionality:**
+- Four categories: Work, Personal, Health, Learning
 - When adding a task, show a dropdown to pick the category
-- Each task shows a small colored dot or badge indicating its category
-- Add filter buttons at the top: "All", "Work", "Personal", "Health", "Learning"
+- Each task shows a small vertical color bar indicating its category
+- Show the category name as a small uppercase label on each task
+- Add pill-shaped filter buttons at the top: "All", "Work", "Personal", "Health", "Learning"
 - Clicking a filter shows only tasks in that category
 - "All" shows everything
-- Active filter button should be visually highlighted
+- Active filter button fills with the category color
 - Categories are saved in localStorage along with the tasks
-- Keep the existing dark mode design
+
+**Design:**
+- Use MUTED, sophisticated colors, not bright primaries:
+  - Work: dusty blue (#7C9CBF)
+  - Personal: sage green (#8BB896)
+  - Health: terracotta (#D4896A)
+  - Learning: lavender (#B08FCF)
+- Category indicator should be a thin vertical bar (3px wide), not a dot
+- Filter buttons should be pill-shaped with a border, not rectangular
+- Active "All" filter uses warm white, category filters use their own color
+- Custom styled select dropdown (hide native arrow, add SVG chevron)
+- Group the search bar and filters into a toolbar card with subtle border
+- Keep the existing warm dark design, do not introduce cold blues
 
 ---
 
@@ -27,7 +41,7 @@ This is the agent loop in action: it does not start from scratch. It reads what
 ## What to Expect
 
 - A category dropdown appears next to the task input
-- Colored filter buttons appear above the task list
-- Each task shows its category color
+- Pill-shaped filter buttons appear above the task list
+- Each task shows its category as a colored vertical bar and small label
 - Switching filters instantly shows/hides tasks
 - Old tasks (without categories) still work