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>

lib/api.ts

@@ -466,6 +466,30 @@ export async function getFundingSnapshot(): Promise<FundingSnapshot> {
   return fetchJson<FundingSnapshot>('/funding/snapshot')
 }
 
+// ── Macro snapshot (BTC page Macro Bottom tab) ──────────────────────────────
+export interface MacroSnapshot {
+  ok: boolean
+  error?: string
+  date?: string
+  captured_at?: string
+  indicators?: {
+    ahr999: number | null
+    altcoin_season_index: number | null
+    fear_greed: number | null
+    fear_greed_label: string | null
+    btc_dominance_pct: number | null
+    eth_btc_ratio: number | null
+    stablecoin_supply_usd: number | null
+    etf_flow_net_usd_1d: number | null
+    btc_open_interest_usd: number | null
+  }
+  composite_score?: number | null
+  regime_label?: string | null
+}
+export async function getMacroSnapshot(): Promise<MacroSnapshot> {
+  return fetchJson<MacroSnapshot>('/macro/snapshot')
+}
+
 // ── Telegram alerts ─────────────────────────────────────────────────────────
 export interface TelegramStatus {
   configured: boolean