feat(runtime): add integration hardening and diagnostics

components/maze32_web/include/maze32_gateway.h

@@ -19,6 +19,8 @@ extern "C" {
 #define MAZE32_GATEWAY_QUEUE_LIMIT 12U
 #define MAZE32_GATEWAY_OUTGOING_LIMIT 768U
 #define MAZE32_GATEWAY_RATE_LIMIT_PER_SECOND 20U
+#define MAZE32_GATEWAY_RATE_LIMIT_CLOSE_THRESHOLD 40U
+#define MAZE32_GATEWAY_PLAYER_LATENCY_BUDGET_MS 250U
 
 typedef struct {
     int active;
@@ -26,14 +28,36 @@ typedef struct {
     uint32_t last_client_sequence;
     uint64_t rate_window_started_ms;
     unsigned int messages_in_window;
+    int closing;
 } maze32_gateway_connection_t;
 
 typedef struct {
     int socket_fd;
     size_t length;
+    int drop_if_busy;
     char payload[MAZE32_GATEWAY_OUTGOING_LIMIT];
 } maze32_gateway_outgoing_t;
 
+typedef struct {
+    uint32_t connection_high_water;
+    uint32_t queue_high_water;
+    uint32_t messages_received;
+    uint32_t messages_sent;
+    uint32_t messages_dropped;
+    uint32_t send_failures;
+    uint32_t malformed_messages;
+    uint32_t oversized_messages;
+    uint32_t rate_limited_messages;
+    uint32_t accepted_game_commands;
+    uint32_t matches_started;
+    uint32_t matches_completed;
+    uint32_t matches_reset;
+    uint64_t maximum_handler_us;
+    uint64_t maximum_send_us;
+    size_t minimum_internal_free_bytes;
+    size_t minimum_internal_largest_block_bytes;
+} maze32_gateway_metrics_t;
+
 typedef struct {
     httpd_handle_t server;
     maze32_lobby_t lobby;
@@ -45,6 +69,8 @@ typedef struct {
     unsigned int suggestion_index;
     esp_timer_handle_t countdown_timer;
     esp_timer_handle_t reconnect_timer;
+    esp_timer_handle_t finish_timer;
+    maze32_gateway_metrics_t metrics;
     maze32_maze_t maze;
     maze32_maze_workspace_t maze_workspace;
     maze32_game_t game;
@@ -56,6 +82,8 @@ void maze32_gateway_set_server(maze32_gateway_t* gateway, httpd_handle_t server)
 esp_err_t maze32_gateway_register(httpd_handle_t server, maze32_gateway_t* gateway);
 void maze32_gateway_close_socket(httpd_handle_t server, int socket_fd);
 int maze32_gateway_can_reconfigure(const maze32_gateway_t* gateway);
+size_t maze32_gateway_format_diagnostics(maze32_gateway_t* gateway, char* output,
+                                         size_t output_size);
 
 #ifdef __cplusplus
 }