fix(build): 删除内联 coco.h，为恢复子模块做准备

内联的 53 行 coco.h 缺少 .context/.priority/.p_id 字段，
与 server.c 和 coco/src/core/coro_go.c 不兼容，导致编译失败。

coco/include/coco.h

@@ -1,53 +0,0 @@
-#ifndef COCO_H
-#define COCO_H
-
-#include <stddef.h>
-#include <stdint.h>
-#include <stdbool.h>
-
-#ifdef __cplusplus
-extern "C" {
-#endif
-
-#define COCO_OK                    0
-#define COCO_ERROR                -1
-#define COCO_ERROR_NOMEM          -2
-#define COCO_ERROR_CANCELLED      -3
-#define COCO_ERROR_WOULD_BLOCK    -4
-#define COCO_ERROR_TIMEOUT        -5
-
-typedef struct coco_sched coco_sched_t;
-typedef struct coco_coro coco_coro_t;
-typedef struct coco_timer coco_timer_t;
-
-typedef void (*coco_func_t)(void *arg);
-typedef void (*coco_timer_handler_t)(void *arg);
-
-typedef struct {
-    int         flags;
-    int         stack_size;
-    int         prio;
-    const char *name;
-} coco_go_opts_t;
-
-int  coco_global_sched_start(int num_workers);
-void coco_global_sched_wait(void);
-void coco_global_sched_stop(void);
-
-coco_coro_t *coco_go(coco_func_t func, void *arg);
-coco_coro_t *coco_go_with_opts(coco_func_t func, void *arg, const coco_go_opts_t *opts);
-coco_coro_t *coco_self(void);
-int  coco_cancel(coco_coro_t *coro);
-coco_sched_t *coco_sched_get_current(void);
-
-ssize_t coco_read(int fd, void *buf, size_t len);
-ssize_t coco_write(int fd, const void *buf, size_t len);
-
-coco_timer_t *coco_timer(uint32_t ms, coco_timer_handler_t handler, void *arg);
-void coco_timer_cancel(coco_timer_t *timer);
-
-#ifdef __cplusplus
-}
-#endif
-
-#endif /* COCO_H */