style: standardize layout widths and padding across all pages

Ensure consistent spacing and alignment between header, main content, and footer:
- Update Navbar to use max-w-7xl and px-8 (matching Footer)
- Standardize all page containers to use px-8 py-12 padding
- Change home page from max-w-5xl to max-w-7xl for consistency
- Update all 12 pages to use consistent padding (px-8 py-12 instead of p-8)

This creates a unified visual alignment across the entire application,
with all content sections (navbar, main, footer) using the same
max-width (7xl) and horizontal padding (px-8).

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

components/layout/Navbar.tsx

@@ -20,7 +20,7 @@ export function Navbar() {
 
   return (
     <nav className="sticky top-0 z-50 w-full border-b bg-background/95 backdrop-blur supports-[backdrop-filter]:bg-background/60">
-      <div className="container mx-auto px-4">
+      <div className="max-w-7xl mx-auto px-8">
         <div className="flex h-16 items-center justify-between">
           {/* Logo */}
           <Link href="/" className="flex items-center space-x-2 font-bold text-xl">