Relay pairing offer v2 (E2EE) + host connections

packages/relay/src/base64.ts

@@ -5,7 +5,14 @@ export function arrayBufferToBase64(buffer: ArrayBuffer): string {
 }
 
 export function base64ToArrayBuffer(base64: string): ArrayBuffer {
-  const bytes = toByteArray(base64);
+  const normalized = (() => {
+    const trimmed = base64.trim();
+    const standard = trimmed.replace(/-/g, "+").replace(/_/g, "/");
+    const padLen = (4 - (standard.length % 4)) % 4;
+    return standard + "=".repeat(padLen);
+  })();
+
+  const bytes = toByteArray(normalized);
   const out = new Uint8Array(bytes.byteLength);
   out.set(bytes);
   return out.buffer;