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/schfs-phase2-mount.md

@@ -0,0 +1,45 @@
+---
+name: schfs-phase2-mount
+description: "SchFS phase 2 is done — the kernel mounts real images read-only; run `make schfs-check` after touching kernel/fs/schfs"
+metadata: 
+  node_type: memory
+  type: project
+  originSessionId: a665e14b-86bd-4b41-a228-51377f3e9225
+  modified: 2026-08-03T12:37:43.088Z
+---
+
+**Phase 2 done (2026-08-02):** the kernel mounts a SchFS volume read-only at
+boot and it is verified end to end. Phase 1 notes: [[schfs-btree-phase1]].
+
+Layout — everything but `kmount.c` compiles into *both* the kernel and the host
+tools, so writer and reader cannot drift:
+
+- `kernel/fs/schfs/vol.c` uberblock ring, `obj.c` read side, `objw.c` write side
+  (host only until phase 3), `kmount.c` buffer-cache bdev + boot mount.
+- `tools/mkschfs.c` builds images, `tools/schfs_fsck.c` verifies/lists/extracts.
+
+**Run `make schfs-check`** (B-tree + round-trip) after any change under
+`kernel/fs/schfs`. `tools/mutate.sh` injects six bugs and fails if any survives.
+
+Boot-testing: `make ramroot` first (root from RAM leaves device 1 free), then
+`make qemu-schfs`, then `cat /proc/schfs`. Unattended:
+`tools\bootcheck.ps1 -SchFS` drives the shell over serial and asserts on the
+transcript — see [[schunix-verify-by-driving-shell]].
+
+**Traps that cost real time, all fixed:**
+
+- The root's object id must be *reserved*; starting `next_objectid` at it made
+  the first directory become the root, so it contained itself.
+- Range callbacks get pointers into the cursor's block buffer, which any nested
+  lookup overwrites. Directory iteration copies each entry out first.
+- A 4096-byte block will not fit on the 4096-byte kernel stack (KSTACKSIZE).
+  The kstack canary catches it as "kstack overflow".
+- Extents only merge if the whole run is allocated before any tree write.
+
+Full write-up, including why the design doc's phase list changed, is in
+`docs/architecture/schfs.md` §8-9.
+
+**Superseded on 2026-08-03 by [[schfs-phase3-writes]]** — writes are done, and
+free space is *derived from the tree at mount*, not tracked as tree keys as
+planned here. The VFS work is still outstanding, and also unblocks per-pid
+`/proc` for ps/top ([[schunix-devfs-procfs]]).