feat: implement the ESP32 opponent

include/bot_player.h

@@ -1,5 +1,25 @@
 #pragma once
 
-#include "app_interfaces.h"
+#include <stdbool.h>
 
-typedef struct { random_source_t random; scheduler_t scheduler; } bot_player_t;
+#include "app_interfaces.h"
+#include "game_types.h"
+
+typedef uint8_t bot_cell_t;
+enum { BOT_CELL_UNKNOWN, BOT_CELL_MISS, BOT_CELL_HIT, BOT_CELL_BLOCKED };
+typedef struct { bool hit; bool sunk; } bot_shot_result_t;
+
+typedef struct {
+  random_source_t random;
+  scheduler_t scheduler;
+  bot_cell_t knowledge[kBotKnowledgeCellCount];
+  bool turn_pending;
+} bot_player_t;
+
+void bot_player_init(bot_player_t *bot, random_source_t random, scheduler_t scheduler);
+bool bot_player_next_shot(bot_player_t *bot, coordinate_t *coordinate);
+void bot_player_record_result(bot_player_t *bot, coordinate_t coordinate, const bot_shot_result_t *result);
+bool bot_player_schedule_turn(bot_player_t *bot);
+void bot_player_cancel_turn(bot_player_t *bot);
+
+_Static_assert(sizeof(bot_player_t) <= 160, "bot state grew beyond fixed budget");