Layout Simplification: Use `MainAxisAlignment.spaceBetween` Instead of `Spacer`

[ajaxspace]

Problem:
Spacer() is used inside a Row to separate items, but MainAxisAlignment.spaceBetween provides a cleaner and more explicit solution:

Row(
  children: [
    const Text('Your Workspaces', ...),
    const Spacer(), // ❌ unnecessary widget depth
    IconButton(...),
  ],
);

Issues:

• Adds an extra widget (Spacer) purely for layout
• Slightly harder to reason about compared to declarative mainAxisAlignment
• Reduces visual clarity for simple layouts

---

✅ Recommendation

Use mainAxisAlignment: MainAxisAlignment.spaceBetween to handle spacing at the layout level:

Row(
  mainAxisAlignment: MainAxisAlignment.spaceBetween,
  children: [
    const Text(
      'Your Workspaces',
      style: TextStyle(
        fontSize: 16,
        fontWeight: FontWeight.bold,
        color: Colors.white,
      ),
    ),
    IconButton(
      icon: const Icon(Icons.add, color: Colors.white, size: 20),
      padding: EdgeInsets.zero,
      constraints: const BoxConstraints(),
      onPressed: () {},
    ),
  ],
);

---

Impact:

• Cleaner layout code
• Eliminates unnecessary widgets
• Improves readability and visual intent

Prefer Spacer only when flexible or proportional space is required — not for fixed separation between two items.