feat: Add stellar key handling files

Author: Keyur279

apps/stellar_app/stellar_priv.h

@@ -0,0 +1,67 @@
+/**
+ * @file    stellar_priv.h
+ * @author  Cypherock X1 Team
+ * @brief   Support for stellar app internal operations
+ *          This file is defined to separate Stellar's internal use
+ * functions, flows, common APIs
+ * @copyright Copyright (c) 2025 HODL TECH PTE LTD
+ * <br/> You may obtain a copy of license at <a href="https://mitcc.org/"
+ * target=_blank>https://mitcc.org/</a>
+ */
+#ifndef STELLAR_PRIV_H
+#define STELLAR_PRIV_H
+/*****************************************************************************
+ * INCLUDES
+ *****************************************************************************/
+#include <stdint.h>
+#include <stellar/core.pb.h>
+
+#include "stellar_context.h"
+
+/*****************************************************************************
+ * TYPEDEFS
+ *****************************************************************************/
+typedef struct {
+  /**
+   * The structure holds the wallet information of the transaction.
+   * @note Populated by stellar_handle_initiate_query()
+   */
+  stellar_sign_txn_initiate_request_t init_info;
+
+  // remembers the allocated buffer for holding complete unsigned transaction
+  uint8_t *transaction;
+
+  // decoded transaction structures
+  stellar_transaction_t *txn;
+  stellar_payment_t *payment;
+
+} stellar_txn_context_t;
+
+/*****************************************************************************
+ * EXPORTED VARIABLES
+ *****************************************************************************/
+
+/*****************************************************************************
+ * GLOBAL FUNCTION PROTOTYPES
+ *****************************************************************************/
+
+/**
+ * @brief Handler for Stellar public key derivation.
+ * @details This flow expects STELLAR_GET_PUBLIC_KEY_REQUEST_INITIATE_TAG as initial
+ * query, otherwise the flow is aborted
+ *
+ * @param query object for address public key query
+ */
+void stellar_get_pub_keys(stellar_query_t *query);
+
+/**
+ * @brief Handler for signing a transaction on stellar.
+ * @details The expected request type is STELLAR_SIGN_TXN_REQUEST_INITIATE_TAG. The
+ * function controls the complete data exchange with host, user prompts and
+ * confirmations for signing an STELLAR based transaction.
+ *
+ * @param query Reference to the decoded query struct from the host app
+ */
+void stellar_sign_transaction(stellar_query_t *query);
+
+#endif /* STELLAR_PRIV_H */