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>

app/[locale]/case-studies/page.tsx

@@ -271,11 +271,12 @@ function getCopy(locale: string): CaseStudiesCopy {
   }
 }
 
-export function generateMetadata({
-  params: { locale },
+export async function generateMetadata({
+  params,
 }: {
-  params: { locale: string }
-}): Metadata {
+  params: Promise<{ locale: string }>
+}): Promise<Metadata> {
+  const { locale } = await params
   const copy = getCopy(locale)
 
   return {
@@ -302,7 +303,8 @@ const SIGNAL_COLOR: Record<string, string> = {
   DIVERGENCE: '#f5a524',
 }
 
-export default function CaseStudiesPage({ params: { locale } }: { params: { locale: string } }) {
+export default async function CaseStudiesPage({ params }: { params: Promise<{ locale: string }> }) {
+  const { locale } = await params
   const copy = getCopy(locale)
   const isZh = false  // i18n shelved — Chinese branches kept as dead code for future revival; see messages/zh.json