Carry project memory in the repo, with tools/memory-sync.sh

Claude Code keeps per-project memory at <home>/.claude/projects/<key>/,
where <key> is the project's absolute path with every separator and the
drive colon turned into a dash. That makes it both rename-fragile and
machine-specific, and this project has hit each of those once:

  - D:\DEV\Schunix -> D:\DEV\SchOS changed the key, and 43 memories were
    invisible until moved across by hand.
  - Development happens from Windows and from Linux, and each looks in a
    different place for the same checkout.

Committing .claude/memory/ fixes both -- git carries it across renames
and between hosts -- and `import` puts it wherever the local machine
expects. .claude/settings.local.json stays ignored: those are per-machine
permissions.

The colon maps to a dash rather than being dropped. Deleting it gives
D-DEV-SchOS, which matches nothing and silently finds zero memories; that
was the first attempt. On Git Bash the key comes from `cygpath -w`,
because Claude Code is a Windows program and sees D:\DEV\SchOS, not
/d/DEV/SchOS.

.claude/memory/schunix-build-environment.md

@@ -0,0 +1,54 @@
+---
+name: schunix-build-environment
+description: Schunix builds natively on Windows with clang/lld + mingw + Git Bash; WSL is gone because WSL2 needs Hyper-V
+metadata: 
+  node_type: memory
+  type: project
+  originSessionId: 9d8a2aef-bcf0-47a0-96c6-f706efab4a95
+  modified: 2026-08-07T17:19:34.188Z
+---
+
+**Builds natively on Windows. WSL is no longer used at all.** WSL2 runs a real
+Linux kernel in a Hyper-V VM, so it hard-requires virtualisation, and enabling
+that puts the Hyper-V hypervisor under the whole machine — which demotes VMware
+to running nested and slows the box down permanently. Nexoniarz will not enable
+it, and that is a reasonable call.
+
+`make` from **Git Bash** does everything. `run.ps1` builds natively too. The
+toolchain, all already installed:
+
+- **clang + ld.lld + llvm-objcopy/objdump** (`C:\Program Files\LLVM\bin`) —
+  clang is a cross-compiler by construction, so `--target=x86_64-elf` builds the
+  kernel and `--target=i386-elf` the bootloader. No cross-binutils needed.
+- **mingw-w64 gcc** (`scoop install mingw`) for host tools — `tools/mkfs.c`
+  needs `<unistd.h>`/`<dirent.h>`, which the Windows SDK lacks.
+- **make** (`scoop install make`), plus Git Bash's perl/sed/dd/sha256sum.
+
+`run.ps1` prepends all three directories itself, so it works from any shell.
+The Makefile detects Windows via `uname -s` matching `MINGW*` and sets
+`WINHOST`. Ports (musl/mksh/toybox) are **not** rebuilt on Windows — they are
+Linux userland built by configure scripts, already staged in `sysroot/`, and
+the Makefile says so out loud rather than skipping silently. Everything is a
+no-op on Linux, so a Linux/VM build still works identically.
+
+**Five latent bugs the move exposed**, all real, none Windows-specific — see
+`docs/architecture/kernel-history.md` §8 for the two hardest:
+
+1. `kernel.ld` named no `.ltext`/`.ldata`/`.lbss` — with `-mcmodel=large`, LLVM
+   and GCC 13+ put nearly everything there, and orphan placement put them past
+   `end`, so `kinit1(end,...)` handed the allocator live `.lbss`.
+2. `uint64` was `unsigned long` — 64-bit on Linux, **32-bit on Windows** (LLP64).
+   Host tools include the on-disk structs, so this would have silently written
+   images with half-width inode fields. Now data-model-aware + `_Static_assert`.
+3. `syscall_entry` used `%fs:(0)` as scratch — that is the **TCB self-pointer**.
+   GCC's direct `%fs:-8` TLS never reads it; clang materialises the TP from it.
+4. `_start` read `argc`/`argv` via `register ... asm("rdi")`, which is only
+   guaranteed for inline-asm operands. clang read uninitialised stack. Now
+   `lib/start.S`.
+5. lld needs `--image-base=0` for anything linked below 0x400000, and
+   `-m elf_x86_64` on `ld -r -b binary`.
+
+**When a symptom moves as you add printfs, stop printing and use the
+watchpoint.** QEMU `-S -gdb tcp::26000` plus mingw's gdb (`hbreak`, then
+`watch`) named the offending instruction on the first run after three rounds of
+cprintf had failed. See [[schunix-verify-by-driving-shell]].