Fix homepage Tablet layout: Hero grid, Tools icon, About columns, Newsletter/Footer stacking

- Hero.tsx: structural breakpoint reverted from lg: back to md: — the
  smaller CTA/subtitle/icon sizes added during the Mobile pass fit
  comfortably in the ~283px Tablet column, so the original 3-line-wrap
  problem that justified lg: doesn't recur. Tablet gets the real 5/7
  grid (image beside text) again instead of a stacked mobile layout.
- Tools.tsx: full-size (56px) card icon pushed from md: to lg: — at
  Tablet it dwarfed the still-close-to-floor title/description text.
- About.tsx: text/photo flex ratio swapped at Tablet (text gets the
  bigger share, no overlap) vs. the original ratio + overlap trick from
  lg: up, where it was designed for — Tablet's text column was too
  narrow for its fixed-width statement + quote/bio row otherwise.
- Newsletter.tsx/Footer.tsx: the input+button row and the logo/handle/
  legal-links row both went side-by-side at md:, but their surrounding
  columns didn't leave enough width at 768px — pushed to lg:flex-row.

app/components/Footer.tsx

@@ -18,8 +18,12 @@ export function Footer() {
       {/* Footer inner — max-width 1280px, centered */}
       <div className="flex flex-col items-center w-full max-w-[1280px] py-8 md:py-4">
 
-        {/* Three groups: logo | @handle | links — stacked + centered below md */}
-        <div className="flex flex-col md:flex-row items-center md:justify-between gap-6 md:gap-0 px-8 md:px-16 w-full">
+        {/* Three groups: logo | @handle | links — stacked + centered below
+            lg: (was md:). Logo + handle + 5 legal links all side by side
+            with justify-between read too cramped on Tablet — stacked
+            through that range instead, side by side again once there's
+            real room at lg:. */}
+        <div className="flex flex-col lg:flex-row items-center lg:justify-between gap-6 lg:gap-0 px-8 md:px-16 w-full">
 
           {/* Logo: "einfach produktiv" white + "." gold */}
           <div className="flex items-center p-2 shrink-0">