feat(core): add hypersense integration api (#7218)

Co-authored-by: hyperswitch-bot[bot] <148525504+hyperswitch-bot[bot]@users.noreply.github.com>

crates/api_models/src/external_service_auth.rs

@@ -0,0 +1,35 @@
+use common_utils::{id_type, pii};
+use masking::Secret;
+
+#[derive(Debug, serde::Serialize)]
+pub struct ExternalTokenResponse {
+    pub token: Secret<String>,
+}
+#[derive(Debug, serde::Serialize, serde::Deserialize)]
+pub struct ExternalVerifyTokenRequest {
+    pub token: Secret<String>,
+}
+
+#[derive(Debug, serde::Serialize, serde::Deserialize)]
+pub struct ExternalSignoutTokenRequest {
+    pub token: Secret<String>,
+}
+
+#[derive(serde::Serialize, Debug)]
+#[serde(untagged)]
+pub enum ExternalVerifyTokenResponse {
+    Hypersense {
+        user_id: String,
+        merchant_id: id_type::MerchantId,
+        name: Secret<String>,
+        email: pii::Email,
+    },
+}
+
+impl ExternalVerifyTokenResponse {
+    pub fn get_user_id(&self) -> &str {
+        match self {
+            Self::Hypersense { user_id, .. } => user_id,
+        }
+    }
+}