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>

messages/en.json

@@ -4,7 +4,7 @@
     "tabs": {
       "overview": "Overview",
       "trump": "Trump",
-      "btc": "BTC",
+      "vibes": "Vibes",
       "kol": "KOL",
       "trades": "Trades",
       "analytics": "Analytics",