tools: group scripts by what runs them

tools/windows/   .ps1   (pwsh, so usable from Linux and macOS too)
  tools/posix/     .sh
  tools/python/    .py
  tools/           .c and .pl

The .c and .pl files stay at the top level because they are not
host-specific: the build compiles or invokes them on every platform.

Call sites updated in the Makefile, ports/mk/port.mk, docs and the
project memory. The one thing that does not survive a move on its own is
a script deriving the repo root from its own location -- all nine
PowerShell tools used Split-Path $PSScriptRoot -Parent, and memory-sync.sh
used dirname/.., both of which quietly become tools/ one level deeper.
Two levels now.

Two pre-existing Windows failures surfaced while verifying, both real and
neither caused by the move:

  - schfs_fsck.c did not compile under mingw at all: --extract uses
    POSIX mkdir(path,mode), symlink() and link(), none of which mingw
    has. That took the whole tool with it, and `make schfs-check` with
    it. mkdir maps to _mkdir; symlink and link fail loudly rather than
    writing a regular file in their place, because an extracted tree
    that differs from the image while reporting success defeats the
    point of --extract.
  - the round-trip test then failed at `ln -s`, since Git Bash cannot
    create symlinks without developer mode. It skips with a message now.
    Not a fudge: mkschfs's mingw build cannot see a symlink either, so
    the test would have compared a tree with none against an image with
    none and called it a pass -- coverage reporting itself as present
    while being absent.

Verified on Windows: build clean, all seven bootcheck suites green,
make schfs-check passes.

tools/memory-sync.sh

@@ -1,111 +0,0 @@
-#!/bin/sh
-# Move Claude Code's project memory between this repo and the local machine.
-#
-#   tools/memory-sync.sh export   memory on this machine  ->  .claude/memory/
-#   tools/memory-sync.sh import   .claude/memory/         ->  this machine
-#   tools/memory-sync.sh status   show both sides, change nothing
-#
-# Why this exists
-# ---------------
-# Claude Code keeps per-project memory outside the repo, under
-#
-#     <home>/.claude/projects/<key>/memory/
-#
-# where <key> is the project's absolute path with the separators replaced by
-# dashes: D:\DEV\SchOS becomes D--DEV-SchOS, /home/me/dev/SchOS becomes
-# -home-me-dev-SchOS. Two consequences follow, and both have already bitten
-# this project once:
-#
-#   * Renaming the directory orphans the memory. D:\DEV\Schunix -> D:\DEV\SchOS
-#     changed the key, and everything written under the old one became
-#     invisible until it was moved across by hand.
-#   * The key is machine-specific, so memory written on Windows is not where
-#     Linux looks for it, even for the same checkout.
-#
-# Committing the memory to the repo fixes both: git carries it between hosts
-# and across renames, and `import` puts it wherever this particular machine
-# expects to find it. Run `export` after a session that learned something and
-# `import` after cloning or pulling on another machine.
-
-set -eu
-
-usage() {
-    echo "usage: $0 {export|import|status}" >&2
-    exit 2
-}
-
-[ $# -eq 1 ] || usage
-
-# Repo root: this script lives in tools/, so the parent of its directory.
-script_dir=$(CDPATH= cd -- "$(dirname -- "$0")" && pwd)
-repo=$(CDPATH= cd -- "$script_dir/.." && pwd)
-repo_mem="$repo/.claude/memory"
-
-# The absolute path Claude Code itself sees. Under Git Bash `pwd` gives
-# /d/DEV/SchOS, but Claude Code is a Windows program and uses D:\DEV\SchOS, so
-# the key must be derived from the Windows form or it will not match.
-native_path="$repo"
-case "$(uname -s)" in
-MINGW* | MSYS* | CYGWIN*)
-    if command -v cygpath >/dev/null 2>&1; then
-        native_path=$(cygpath -w "$repo")
-    fi
-    ;;
-esac
-
-# Encode: every separator becomes a dash, and so does the drive colon.
-#
-#   D:\DEV\SchOS        ->  D--DEV-SchOS
-#   /home/me/dev/SchOS  ->  -home-me-dev-SchOS
-#
-# The colon maps to a dash rather than being deleted -- that is where the
-# doubled dash in the Windows form comes from, and dropping it instead yields
-# D-DEV-SchOS, which matches nothing.
-key=$(printf '%s' "$native_path" | tr '/\\:' '---')
-
-home_dir=${HOME:-$USERPROFILE}
-host_mem="$home_dir/.claude/projects/$key/memory"
-
-count() { [ -d "$1" ] && find "$1" -name '*.md' 2>/dev/null | wc -l | tr -d ' ' || echo 0; }
-
-case "$1" in
-status)
-    echo "repo:          $repo"
-    echo "as Claude sees it: $native_path"
-    echo "project key:   $key"
-    echo
-    echo "in repo:       $repo_mem"
-    echo "               $(count "$repo_mem") memories"
-    echo "on this host:  $host_mem"
-    echo "               $(count "$host_mem") memories"
-    ;;
-
-export)
-    if [ ! -d "$host_mem" ]; then
-        echo "memory-sync: nothing to export -- no memory at $host_mem" >&2
-        echo "  (is the project key right? run: $0 status)" >&2
-        exit 1
-    fi
-    mkdir -p "$repo_mem"
-    # Copy rather than mirror: deleting from the repo is a git operation and
-    # should be visible in a diff, not a side effect of running a sync script.
-    cp "$host_mem"/*.md "$repo_mem"/ 2>/dev/null || true
-    echo "exported $(count "$repo_mem") memories to .claude/memory/"
-    echo "commit them to carry them to your other machines."
-    ;;
-
-import)
-    if [ ! -d "$repo_mem" ]; then
-        echo "memory-sync: nothing to import -- no .claude/memory/ in this repo" >&2
-        exit 1
-    fi
-    mkdir -p "$host_mem"
-    cp "$repo_mem"/*.md "$host_mem"/ 2>/dev/null || true
-    echo "imported $(count "$host_mem") memories to:"
-    echo "  $host_mem"
-    ;;
-
-*)
-    usage
-    ;;
-esac