🐛 fix: type mismatch in dtp_download_file corrupted payload_id

dtp_prepare_session() expects (uint8_t timeout, uint8_t payload_id,
uint16_t mtu) but we were passing (uint32_t, uint16_t, uint32_t).
The wider types shifted subsequent arguments on the stack, causing
the server to receive payload_id=4 (high byte of mtu=1024) instead
of the actual payload_id=1.

Fix: match dtp_download_file signature to the library's exact types.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: mse-pn

satdeploy-agent/include/satdeploy_agent.h

@@ -120,12 +120,12 @@ int backup_list(const char *app_name, backup_list_callback callback, void *user_
  * @param expected_size Expected file size (0 to skip size check).
  * @param mtu Max transmission unit (0 = use default 1024).
  * @param throughput Target throughput in bytes/s (0 = use default 10 MB/s).
- * @param timeout Transfer timeout in seconds (0 = use default 60).
+ * @param timeout Transfer timeout in seconds (0 = use default 60, max 255).
  * @return 0 on success, -1 on failure.
  */
-int dtp_download_file(uint32_t server_node, uint16_t payload_id,
+int dtp_download_file(uint32_t server_node, uint8_t payload_id,
                       const char *dest_path, uint32_t expected_size,
-                      uint32_t mtu, uint32_t throughput, uint32_t timeout);
+                      uint16_t mtu, uint32_t throughput, uint8_t timeout);
 
 /**
  * Save app deployment metadata.

satdeploy-agent/src/dtp_client.c

@@ -98,9 +98,9 @@ static void on_download_release(dtp_t *session) {
     /* Nothing to clean up - context is on stack */
 }
 
-int dtp_download_file(uint32_t server_node, uint16_t payload_id,
+int dtp_download_file(uint32_t server_node, uint8_t payload_id,
                       const char *dest_path, uint32_t expected_size,
-                      uint32_t mtu, uint32_t throughput, uint32_t timeout) {
+                      uint16_t mtu, uint32_t throughput, uint8_t timeout) {
     if (dest_path == NULL) {
         return -1;
     }