chore: add RP_ID, RP_NAME, and RESEND_API_KEY to env example

.env.example

@@ -54,3 +54,21 @@ S3_ACCESS_KEY_ID=""
 S3_SECRET_ACCESS_KEY=""
 S3_BUCKET_NAME=""
 S3_PUBLIC_URL=""
+
+# -----------------------------------------------------------------------------
+# PASSKEY (WebAuthn)
+# -----------------------------------------------------------------------------
+# RP ID: Your domain without protocol (e.g., "localhost" or "deckyvault.xyz")
+RP_ID="localhost"
+
+# RP Name: Human-readable name shown in passkey prompts
+RP_NAME="DeckyVault"
+
+# -----------------------------------------------------------------------------
+# EMAIL
+# -----------------------------------------------------------------------------
+# Resend API key for sending OTP emails (optional — falls back to console logging)
+RESEND_API_KEY=""
+
+# Email sender address
+EMAIL_FROM="DeckyVault <noreply@deckyvault.xyz>"