add page cache with read-ahead and dirty writeback, file-backed and anonymous mmap with CoW, VAD-based virtual memory replacing the old user region model, PFN database with eviction and reclaim, file identity for cross-open section sharing, FAT32 path cache and per-file cluster chain cache, serial.sys for COM1 keyboard input, xHCI MSI with INTx and polled fallback, PciEnableMsiAuto, waitable input queue, KeWaitForAnyEvent, per-process thread info syscall, expanded kernel stats (PFN/PTE/VAD/file-cache/disk), pool allocation tags, async I/O user buffer locking, file flush on close, add docs.md.

code/kernel/ke_semaphore.c

@@ -68,6 +68,7 @@ __declspec(dllexport) void KeSignalSemaphore(SEMAPHORE* sem) {
         // consuming a count later.
         LIST_ENTRY* node = ListPopHead(&sem->WaitList);
         THREAD* waiter   = CONTAINING_RECORD(node, THREAD, SchedulerLink);
+        KeSetThreadWaitList(waiter, (LIST_ENTRY*)0);
         KeReleaseSpinlock(&sem->Lock, flags);
         KeUnblockThreadWithStatus(waiter, STATUS_SUCCESS);
         return;