V4V: keysend payments, recipient breakdown, and episode nudge

- Add payKeysendViaNWC for node pubkey recipients with TLV records
- Route V4V payments to keysend or LNURL-pay based on recipient type
- Show recipient split breakdown in V4V panel (name + percentage)
- Add V4V nudge: brief tooltip when V4V episode starts (once per session)
- Highlight V4V button in amber when episode has recipients but streaming off
- Enhanced V4V badge in episode list with lightning icon and pill style

src/index.css

@@ -99,6 +99,17 @@ body {
   animation: fade-in 150ms ease-out;
 }
 
+/* V4V nudge — slides in, holds, then fades out */
+@keyframes nudge-in {
+  0% { opacity: 0; transform: translateY(4px); }
+  10% { opacity: 1; transform: translateY(0); }
+  80% { opacity: 1; }
+  100% { opacity: 0; }
+}
+.animate-fade-in {
+  animation: nudge-in 5s ease-out forwards;
+}
+
 /* Toast slide-in */
 @keyframes toast-in {
   from { opacity: 0; transform: translateX(16px); }