fix: adapt tests and fix bugs from enhancements rebase onto main

- Fix transport_tcp.c: initialize server->ssl_ctx to NULL
  (prevents SSL_CTX_free on garbage when server_create_tls fails)
- Fix test_transport_tcp.c: client_create now sets fd=-1, family=AF_UNSPEC
- Fix test_transport_tcp.c: server address family may be AF_INET or AF_INET6
- Fix test_file_sendfile.c: send_path=false protocol includes file_type prefix

src/shared/config.h

@@ -40,6 +40,8 @@ typedef struct Config {
   char* tls_cert;
   char* tls_key;
   char* tls_ca;
+  bool follow_symlinks;
+  bool partial;
 } Config;
 
 #define PROTOCOL_VERSION "1.3.0"