Fix respawn/spawn timers racing ahead under multi-threading

POSIX clock() sums CPU time across every thread in the process, unlike
Windows' clock() which tracks wall-clock milliseconds. With several
worker threads running, respawn/spawn/AI timers based on clock() raced
far ahead of real elapsed time. Switch spawn-timer bookkeeping to
time(NULL)/time_t (seconds) throughout the world server, and add a
portable clock() shim in sockets.h (backed by CLOCK_MONOTONIC,
millisecond resolution) for remaining call sites so CLOCKS_PER_SEC==1000
still holds like it did on Windows.

Also: fix MapDelay/VisualDelay/WorldDelay being passed to usleep() (us)
without converting from their configured milliseconds; fix the shutdown
timer likewise; stop leaking the temporary actor used to run an NPC's
AIP script; fix CleanDrops() skipping the element that shifts into
position after an erase.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

Src/Common/sockets.h

@@ -62,6 +62,29 @@
 #include <assert.h>
 #include <math.h>
 #include <cmath>
+
+#ifndef _WIN32
+// The entire codebase was written against Windows' clock(), which returns a
+// monotonic MILLISECOND counter (CLOCKS_PER_SEC == 1000) that closely tracks
+// wall-clock time for a normal single-threaded process. POSIX clock() is
+// completely different: microsecond resolution (CLOCKS_PER_SEC == 1,000,000)
+// AND it sums CPU time across every thread in the process. With several
+// worker threads running, POSIX clock() races far ahead of real elapsed
+// time, breaking every cooldown/timer/AI-tick comparison in the game logic
+// (movement, attacks, aggro, respawns, buffs, ...). Redirect clock() to a
+// real wall-clock millisecond counter so CLOCKS_PER_SEC==1000 holds like it
+// did on Windows, without having to touch every call site individually.
+#include <time.h>
+static inline long __rose_portable_clock()
+{
+    struct timespec ts;
+    clock_gettime(CLOCK_MONOTONIC, &ts);
+    return (long)(ts.tv_sec * 1000L + ts.tv_nsec / 1000000L);
+}
+#undef CLOCKS_PER_SEC
+#define CLOCKS_PER_SEC 1000
+#define clock() __rose_portable_clock()
+#endif
 #include <map>
 #include "pthread.h"
 #include <vector>
@@ -78,8 +101,8 @@ typedef char SBYTE;
 typedef unsigned char BYTE;
 typedef short SWORD;
 typedef unsigned short WORD;
-typedef long SDWORD;
-typedef unsigned long DWORD;
+typedef int SDWORD;
+typedef unsigned int DWORD;
 typedef long long SQWORD;
 typedef unsigned long long QWORD;
 #ifdef _WIN32