fix(platform): resolve ODR violation in make_timespec/calc_wait_time inline functions

Problem:
- Both linux/get_wait_time.h and posix/get_wait_time.h define inline functions
  make_timespec() and calc_wait_time() in namespace ipc::detail
- On Linux, semaphore uses posix implementation, but may include both headers
- This causes ODR (One Definition Rule) violation - undefined behavior
- Different inline function definitions with same name violates C++ standard
- Manifested as test failures in SemaphoreTest::WaitTimeout

Solution:
- Add platform-specific namespace layer between ipc and detail:
  - linux/get_wait_time.h: ipc::linux::detail::make_timespec()
  - posix/get_wait_time.h: ipc::posix::detail::make_timespec()
- Update all call sites to use fully qualified names:
  - linux/condition.h: linux::detail::make_timespec()
  - linux/mutex.h: linux::detail::make_timespec() (2 places)
  - posix/condition.h: posix::detail::make_timespec()
  - posix/mutex.h: posix::detail::make_timespec() (2 places)
  - posix/semaphore_impl.h: posix::detail::make_timespec()

This ensures each platform's implementation is uniquely named, preventing
ODR violations and ensuring correct function resolution at compile time.

src/libipc/platform/linux/condition.h

@@ -27,7 +27,7 @@ public:
                 return false;
             }
         } else {
-            auto ts = detail::make_timespec(tm);
+            auto ts = linux::detail::make_timespec(tm);
             int eno = A0_SYSERR(a0_cnd_timedwait(native(), static_cast<a0_mtx_t *>(mtx.native()), {ts}));
             if (eno != 0) {
                 if (eno != ETIMEDOUT) {

src/libipc/platform/linux/get_wait_time.h

@@ -10,6 +10,7 @@
 #include "a0/err_macro.h"
 
 namespace ipc {
+namespace linux {
 namespace detail {
 
 inline bool calc_wait_time(timespec &ts, std::uint64_t tm /*ms*/) noexcept {
@@ -43,4 +44,5 @@ inline timespec make_timespec(std::uint64_t tm /*ms*/) noexcept(false) {
 }
 
 } // namespace detail
+} // namespace linux
 } // namespace ipc

src/libipc/platform/linux/mutex.h

@@ -25,7 +25,7 @@ public:
     bool lock(std::uint64_t tm) noexcept {
         if (!valid()) return false;
         for (;;) {
-            auto ts = detail::make_timespec(tm);
+            auto ts = linux::detail::make_timespec(tm);
             int eno = A0_SYSERR(
                 (tm == invalid_value) ? a0_mtx_lock(native()) 
                                       : a0_mtx_timedlock(native(), {ts}));
@@ -56,7 +56,7 @@ public:
 
     bool try_lock() noexcept(false) {
         if (!valid()) return false;
-        int eno = A0_SYSERR(a0_mtx_timedlock(native(), {detail::make_timespec(0)}));
+        int eno = A0_SYSERR(a0_mtx_timedlock(native(), {linux::detail::make_timespec(0)}));
         switch (eno) {
         case 0:
             return true;

src/libipc/platform/posix/condition.h

@@ -115,7 +115,7 @@ public:
             }
             break;
         default: {
-                auto ts = detail::make_timespec(tm);
+                auto ts = posix::detail::make_timespec(tm);
                 int eno;
                 if ((eno = ::pthread_cond_timedwait(cond_, static_cast<pthread_mutex_t *>(mtx.native()), &ts)) != 0) {
                     if (eno != ETIMEDOUT) {

src/libipc/platform/posix/get_wait_time.h

@@ -10,6 +10,7 @@
 #include "libipc/utility/log.h"
 
 namespace ipc {
+namespace posix {
 namespace detail {
 
 inline bool calc_wait_time(timespec &ts, std::uint64_t tm /*ms*/) noexcept {
@@ -36,4 +37,5 @@ inline timespec make_timespec(std::uint64_t tm /*ms*/) noexcept(false) {
 }
 
 } // namespace detail
+} // namespace posix
 } // namespace ipc

src/libipc/platform/posix/mutex.h

@@ -196,7 +196,7 @@ public:
     bool lock(std::uint64_t tm) noexcept {
         if (!valid()) return false;
         for (;;) {
-            auto ts = detail::make_timespec(tm);
+            auto ts = posix::detail::make_timespec(tm);
             int eno = (tm == invalid_value) 
                 ? ::pthread_mutex_lock(mutex_) 
                 : ::pthread_mutex_timedlock(mutex_, &ts);
@@ -230,7 +230,7 @@ public:
 
     bool try_lock() noexcept(false) {
         if (!valid()) return false;
-        auto ts = detail::make_timespec(0);
+        auto ts = posix::detail::make_timespec(0);
         int eno = ::pthread_mutex_timedlock(mutex_, &ts);
         switch (eno) {
         case 0:

src/libipc/platform/posix/semaphore_impl.h

@@ -88,7 +88,7 @@ public:
                 return false;
             }
         } else {
-            auto ts = detail::make_timespec(tm);
+            auto ts = posix::detail::make_timespec(tm);
             if (::sem_timedwait(h_, &ts) != 0) {
                 if (errno != ETIMEDOUT) {
                     ipc::error("fail sem_timedwait[%d]: tm = %zd, tv_sec = %ld, tv_nsec = %ld\n",