Redesign header icons/account-cart chip, light footer, fix sticky-footer gap

- New shared SVG icon set (src/components/ui/icons.tsx): Menu, User,
  Cart, Close, ChevronLeft — replaces emoji (☰ 👤 🛒 ✕) across the
  header, and the literal "←" text arrow on every "view more"-style
  link (SectionTitle's action, the mega-menu link, BlogCarousel's
  "ادامه مطلب").
- Header desktop account/cart area redesigned as a borderless chip:
  cart icon button (right) + divider + account icon-badge/two-line
  "حساب کاربری / ورود/ثبت‌نام" (left), matching a supplied reference.
  Got the RTL DOM order backwards on the first pass (cart needs to be
  first in DOM to render rightmost) and corrected it.
- Header logo: -10px (was already doubled from an earlier request).
- Footer: background is now bg-[#9a21291a] (exact hex given, not a
  token substitute) with black text throughout instead of solid
  dark-red/white; footer logo doubled; the meshkee-credit logo gets
  brightness-0 so the white source asset stays visible on the new
  light background.
- Fixed a real layout bug: <main> had no flex-1, so on any page
  shorter than the viewport the footer stuck to the content instead of
  the bottom of the screen, leaving a gap of bare background beneath
  it. Standard sticky-footer flex fix.
- CONTEXT.md: documented the icon set, the account/cart chip's RTL DOM
  ordering (to stop this regressing again), and the footer's new
  color scheme + the flex-1 fix.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

src/components/cart/CartButton.tsx

@@ -1,6 +1,7 @@
 "use client";
 
 import { useCart } from "@/context/CartContext";
+import { CartIcon } from "@/components/ui/icons";
 
 export function CartButton() {
   const { itemCount, openPopup } = useCart();
@@ -9,12 +10,12 @@ export function CartButton() {
     <button
       type="button"
       onClick={openPopup}
-      className="relative flex items-center gap-1.5 rounded-lg border border-border px-3 py-2 transition-colors hover:border-red hover:text-red"
+      aria-label="سبد خرید"
+      className="relative flex h-11 w-11 shrink-0 items-center justify-center rounded-xl bg-surface text-foreground transition-colors hover:text-red"
     >
-      <span aria-hidden>🛒</span>
-      <span className="hidden sm:inline">سبد خرید</span>
+      <CartIcon className="h-5 w-5" />
       {itemCount > 0 && (
-        <span className="absolute -top-1.5 -left-1.5 flex h-5 min-w-5 items-center justify-center rounded-full bg-red px-1 text-[10px] font-bold text-white">
+        <span className="absolute -top-1.5 -right-1.5 flex h-5 min-w-5 items-center justify-center rounded-full bg-red px-1 text-[10px] font-bold text-white">
           {itemCount}
         </span>
       )}