feat(web): add "upgrade account" CTA above sidebar profile for free users

Shows a brand-tinted "Hesabını Yükselt" badge above the username in the
sidebar footer, linking to the subscription page. Hidden for users with
an active paid plan. Renders in desktop (expanded + collapsed icon
variant), and the mobile drawer.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

apps/web/src/messages/tr.json

@@ -54,6 +54,7 @@
     "referrals": "Referanslar",
     "serviceTest": "Servis Test",
     "upgradePlan": "Plan Yükselt",
+    "upgradeAccount": "Hesabını Yükselt",
     "welcome": "Sase.tr'ye hoş geldiniz",
     "primaryNav": "Ana navigasyon",
     "openMenu": "Menüyü aç",