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.

runa.bat

@@ -7,7 +7,7 @@
 -device ide-hd,bus=ahci.0,drive=disk0 ^
 -serial stdio ^
 -M q35 ^
--m 256M ^
+-m 128M ^
 -smp cpus=4,cores=4,threads=1,sockets=1 ^
 -netdev user,id=net0,hostfwd=tcp::8080-:8080 ^
 -device rtl8139,netdev=net0 ^