feat: improve invoice view responsiveness and settings UX

- Replace custom invoice items table with responsive DataTable component
- Fix server/client component error by creating InvoiceItemsTable client
  component
- Merge danger zone with actions sidebar and use destructive button
  variant
- Standardize button text sizing across all action buttons
- Remove false claims from homepage (testimonials, ratings, fake user
  counts)
- Focus homepage messaging on freelancers with honest feature
  descriptions
- Fix dark mode support throughout app by replacing hard-coded colors
  with semantic classes
- Remove aggressive red styling from settings, add subtle red accents
  only
- Align import/export buttons and improve delete confirmation UX
- Update dark mode background to have subtle green tint instead of pure
  black
- Fix HTML nesting error in AlertDialog by using div instead of nested p
  tags

This update makes the invoice view properly responsive, removes
misleading marketing claims, and ensures consistent dark mode support
across the entire application.

src/app/invoices/layout.tsx

@@ -1,5 +1,5 @@
-import { Navbar } from "~/components/Navbar";
-import { Sidebar } from "~/components/Sidebar";
+import { Navbar } from "~/components/layout/navbar";
+import { Sidebar } from "~/components/layout/sidebar";
 
 export default function InvoicesLayout({
   children,
@@ -11,10 +11,8 @@ export default function InvoicesLayout({
       <Navbar />
       <div className="flex">
         <Sidebar />
-        <main className="flex-1 min-h-screen bg-background">
-          {children}
-        </main>
+        <main className="bg-background min-h-screen flex-1">{children}</main>
       </div>
     </>
   );
-} 
+}