vfs: everything is a file — dirs, ramfs, character devices

- fs.rs: node-table VFS (root /dev /tmp /etc).  Regular files are
  in-memory ramfs; char devices regenerate content on every read so
  'cat /dev/rtc' shows the live time.  Nodes are stable handles with
  tombstone removal; . and .. path resolution.
- /dev devices: mem (raw physical RAM, offset = address), rtc, pci,
  version, meminfo, null, zero, console (write prints to screen+serial),
  serial.  /etc/motd static file.
- shell: ls, cat, hexdump (hexdump -C style), mkdir, touch, rm; echo
  gains '>' overwrite and '>>' append redirection (append bug fixed:
  first '>' in '>>' was parsed as overwrite)
- boot: fs init + self-test (create/read/write/remove) before the shell
- QEMU verified: file lifecycle, redirection, console/null writes,
  mkdir/touch/rm, hexdump /dev/mem and /tmp/x byte-exact

1 files changed, 6 insertions, 0 deletions

diff --git a/CONTEXT.md b/CONTEXT.md
index 8ee7f6c..5b76eaa 100644
--- a/CONTEXT.md
+++ b/CONTEXT.md
@@ -98,6 +98,9 @@ Single Rust crate (`x86_64-unknown-uefi` target).  Module breakdown:
 - `power.rs` — `ResetSystem`-based shutdown, hlt loop fallback
 - `rtc.rs` — CMOS/RTC clock (ports 0x70/0x71), BCD/12h normalization
 - `pci.rs` — legacy PCI config space (0xCF8/0xCFC), full enumeration
+- `fs.rs` — VFS: dirs, ramfs files, char devices (`/dev/mem`, `rtc`, `pci`,
+  `version`, `meminfo`, `null`, `zero`, `console`, `serial`; `/tmp` ramfs;
+  `/etc/motd`)
 - `gop.rs` — framebuffer access and text rendering
 - `font.rs` — 8×16 bitmap font data
 - `ps2.rs` — PS/2 keyboard driver (polling)
@@ -124,6 +127,9 @@ Single Rust crate (`x86_64-unknown-uefi` target).  Module breakdown:
   (ACPI S5; `halt` keeps the plain hlt loop)
 ✅ **RTC** — CMOS clock read at boot and via `date` (BCD/12h handled)
 ✅ **PCI** — port-based config access, full bus enumeration via `pci`
+✅ **VFS** — “everything is a file”: dirs, ramfs, char devices
+  (`ls`/`cat`/`hexdump`/`mkdir`/`touch`/`rm`, `echo >`/`>>`; devices
+  regenerate on read, `/dev/mem` is raw physical RAM)
 
 ## Target audience