Perfect! Here's a clean, structured Dev Checklist for Day 4, Notion-style, that covers everything you've planned. It includes:

• ✅ Global refresh button logic
• ✅ Card menu: change URL & interval
• ✅ Input validation for refresh time
• ✅ Delete card functionality

🧠 Day 4 – Dev Checklist: Global Control & Per-Card Settings

🔁 Global Refresh Button

• [x] Add a "Refresh All" button at the top or in a utility bar.
• [x] On click:
  • [x] Traverse the global card map (Map<cardId, data>).
  • [x] Clear all existing intervals.
  • [x] Fetch fresh data for each card.
  • [x] Reinitialize setInterval for all.

⚙️ Card Settings Menu

• [x] Add a settings button (e.g., ⚙️ or 🛠) to each card.
• [x] On click, show a small modal or inline UI with:
  • [x] Input field for custom API URL.
  • [x] Input field for refresh interval.
  • [x] Save/Apply button.

✔️ Input Validation for Refresh Interval

• [x] Minimum allowed interval: 10 seconds.
• [x] Maximum allowed interval: (optional, e.g., 5 min).
• [x] Show warning or disable save if:
  • [x] Interval < 10.
  • [x] Invalid number or negative value.