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-layout-migration.md

@@ -0,0 +1,44 @@
+---
+name: schunix-layout-migration
+description: "The bt/ -> ports/ + lib/ + cmd/ restructure done 2026-08-01, and the two build traps it exposed"
+metadata: 
+  node_type: memory
+  type: project
+  originSessionId: d1a1ea76-f919-411c-b0ef-0e1bc5064563
+  modified: 2026-08-01T17:17:12.984Z
+---
+
+Restructured Schunix's tree on 2026-08-01. `bt/` became `ports/` (third-party
+only, Makefile + patches, nothing else), first-party userland split into `lib/`
+(runtime glue) and `cmd/<name>/main.c` (programs), tarballs to `dist/`, and all
+generated output to `build/`. Documented in `docs/layout.md`. Verified: full
+build passes and the image boots to `init: ready (pid 1)`.
+
+**Two traps that bit during this and will bite again:**
+
+1. `ld -r -b binary` derives symbol names from the input file's **path**. The
+   kernel embeds `initcode` and `entryother` this way, and the root Makefile
+   has `--redefine-sym _binary_build_lib_initcode_start=...` lines. Move either
+   blob's build location and the link breaks.
+
+2. **A stamp file inside the directory it guards is always out of date.**
+   `ports/musl`'s `$(SRCDIR)/.patched` rule depended on `$(SRCDIR)`, but
+   creating the stamp bumps that directory's mtime, so the rule re-ran on every
+   build and failed (a patch does not apply twice). Same class of bug in
+   toybox and mksh. Fixed by making `$(SRCDIR)` an order-only prerequisite
+   (`| $(SRCDIR)`) in all three ports.
+
+**A real thing that was silently lost-in-waiting:** musl's patch file claimed
+two modified files; the build tree actually had five. The three undocumented
+ones were in mallocng — two are inert debug tracing under
+`#ifdef SCHUNIX_MALLOC_DEBUG`, but `glue.h` had a **required** build fix
+(forward declarations for `__mmap`/`__madvise`/`__mremap`) that existed only as
+a hand-edit in the build tree. Any `make distclean` would have silently lost
+it. The patch was regenerated from a real diff against pristine musl 1.2.5 and
+dry-run verified.
+
+Backups from that session (delete when confident): the pre-migration tarball
+`~/schunix-backup-20260801-1856.tar.gz` and `~/toybox-known-good`, both inside
+WSL.
+
+See [[schunix-build-environment]], [[schunix-rewrite-priorities]].