fix(platform): Add FreeBSD detection and include detect_plat.h in detail.h

Fixed two critical issues from the rebase:
1. Added LIBIPC_OS_FREEBSD macro definition in detect_plat.h to enable
   FreeBSD platform detection alongside other OS checks
2. Added missing #include "libipc/imp/detect_plat.h" in detail.h to
   properly include platform detection macros

These fixes ensure FreeBSD compilation will work correctly with the
unified platform detection system.

Author: mutouyun

include/libipc/imp/detect_plat.h

@@ -15,6 +15,8 @@
 #elif defined(WIN32) || defined(_WIN32) || defined(__WIN32__) || \
       defined(__NT__) || defined(__MSYS__)
 # define LIBIPC_OS_WIN32
+#elif defined(__FreeBSD__)
+# define LIBIPC_OS_FREEBSD
 #elif defined(__QNX__) || defined(__QNXNTO__)
 # define LIBIPC_OS_QNX
 #elif defined(__APPLE__)

src/libipc/platform/detail.h

@@ -1,6 +1,8 @@
 #ifndef LIBIPC_SRC_PLATFORM_DETAIL_H_
 #define LIBIPC_SRC_PLATFORM_DETAIL_H_
 
+#include "libipc/imp/detect_plat.h"
+
 
 #if defined(__cplusplus)
 
@@ -97,3 +99,4 @@ constexpr const T& (min)(const T& a, const T& b) {
 #endif // defined(__cplusplus)
 #endif // LIBIPC_SRC_PLATFORM_DETAIL_H_
 
+