- 5-phase VFS architecture overhaul (path resolution, dir cache, watch/notify,
symlinks, async API)
- Add character/block device node layer with /dev/null and /dev/zero built-ins
- RegisterDevice() API for custom device nodes with read/write/size callbacks
- Merge TOpenMode + TWriteMode into single TOpenMode enum
(omRead, omWrite, omCreate, omReadWrite, omStream)
- Add stream write support: WriteFile/WriteFileAsync now accept omStream handles
with auto-advancing offset for both device and volume FDs
- Add PPWriteOffsetHook type and writeOffsetCallback field to TFilesystem
- Add PPReadOffsetHook-based streaming reads for FAT32 and ISO9660
- Update all callers (notepad, edit, inio, wasm runner, filepicker, filedispatch,
vterminal, stdio) to new 2-param OpenFile API
- 77 unit tests (0 failures) covering path ops, dir cache, symlinks, watch,
device nodes, and stream read/write
- Add doc/vfs.md — comprehensive public VFS API documentation