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/public/ntlite/status.h

@@ -45,4 +45,26 @@ typedef uint32_t KSTATUS;
 // --- Execution level (0x0060) ---.
 #define STATUS_INVALID_IRQL       ((KSTATUS)0x0060)
 
+// --- Process termination reasons ---.
+// Low values are reserved for ordinary KSTATUS returns. Abnormal process
+// termination uses a high-bit private range so exit statuses cannot collide
+// with normal kernel/API result codes.
+//
+// Layout:
+//   31        : set => abnormal/private status
+//   30..24    : subsystem group
+//   23..0     : group-local reason
+//
+// Group 0x61 is process termination/fault status.
+#define STATUS_PRIVATE_BASE               ((KSTATUS)0x80000000u)
+#define STATUS_PROCESS_BASE               ((KSTATUS)0xE1000000u)
+#define STATUS_PROCESS_KILLED             ((KSTATUS)(STATUS_PROCESS_BASE | 0x0000u))
+#define STATUS_PROCESS_PAGE_FAULT         ((KSTATUS)(STATUS_PROCESS_BASE | 0x0010u))
+#define STATUS_PROCESS_GENERAL_PROTECTION ((KSTATUS)(STATUS_PROCESS_BASE | 0x0011u))
+#define STATUS_PROCESS_ILLEGAL_OPCODE     ((KSTATUS)(STATUS_PROCESS_BASE | 0x0012u))
+#define STATUS_PROCESS_DIVIDE_BY_ZERO     ((KSTATUS)(STATUS_PROCESS_BASE | 0x0013u))
+#define STATUS_PROCESS_BREAKPOINT         ((KSTATUS)(STATUS_PROCESS_BASE | 0x0014u))
+#define STATUS_PROCESS_ALIGNMENT_FAULT    ((KSTATUS)(STATUS_PROCESS_BASE | 0x0015u))
+#define STATUS_PROCESS_UNKNOWN_FAULT      ((KSTATUS)(STATUS_PROCESS_BASE | 0x001Fu))
+
 #define KSUCCESS(s)  ((s) == STATUS_SUCCESS)