feat(macro-vibes): rename BTC Signal → Macro Vibes; add MacroPanel UI

Module rename across page H1, navbar tab, URL (/en/btc → /en/macro),
all metadata/JSON-LD, sitemap, llms.txt, opengraph image, and SystemControl
copy. Old /btc route fully removed.

New components/btc/MacroPanel.tsx polls /api/macro/snapshot and lays out
the 8 indicators in four sections (Valuation / Bottom trigger reference /
Market structure / Sentiment & flows / Positioning) with tone-coloured
values, current-band threshold chips, and a single CoinGlass / source
chart link per card. Composite -100..+100 needle pulses on score change.

Also fixes the pinned bottom-reversal alert on the homepage, which still
linked to the now-404 /en/btc — now routes to /en/macro.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

components/nav/Navbar.tsx

@@ -87,7 +87,7 @@ export default function Navbar() {
   const tabs = [
     { key: '/',          label: t('tabs.overview') },
     { key: '/trump',     label: t('tabs.trump') },
-    { key: '/btc',       label: t('tabs.btc') },
+    { key: '/macro',     label: t('tabs.vibes') },
     { key: '/kol',       label: t('tabs.kol') },
     { key: '/trades',    label: t('tabs.trades') },
     { key: '/analytics', label: t('tabs.analytics') },