feat: end-to-end integrity checks with self-healing; website; installer and Windows fixes

Store::verify compares the whole SQLite projection, every table row for
row, against a fresh projection of the journal; verify_and_heal rebuilds a
drifted database (keeping the old file) at every server start and via the
new books.verify tool, which also re-hashes every blob. The GUI checks the
server's database read-only and every stored file, and shows the result.
rebuild() also drops stale WAL/SHM files.

site/: the wanderbooks website (just site, just publish). install.sh:
OS detection (Windows points to WSL2), C compiler and git checks,
WANDERBOOKS_REPO. Windows: no directory fsync off Unix; .exe-aware lookup.
Repo justfile: check, build, install, demo, site.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01MtYEaR6M6Ybdhm6X98BWNu

install.sh

@@ -3,23 +3,57 @@
 #
 #   curl -fsSL https://git.swaits.com/swaits/wanderbooks/raw/branch/main/install.sh | sh -s -- ~/Books/Acme
 #
+# Linux and macOS. On Windows, run it inside WSL2 (Ubuntu): the GUI opens as
+# a normal window on Windows 11.
+#
 # Installs Rust if needed, then the wanderbooks CLI, MCP server, and GUI
 # (into ~/.cargo/bin), then — given a directory — makes your books there and
 # starts the agent. Without a directory it just installs.
+#
+# WANDERBOOKS_REPO overrides where it installs from (a git URL).
 set -eu
 
-REPO="https://git.swaits.com/swaits/wanderbooks"
+REPO="${WANDERBOOKS_REPO:-https://git.swaits.com/swaits/wanderbooks}"
 
 say() { printf '\033[1m%s\033[0m\n' "$*"; }
+die() { printf '\033[1;31m%s\033[0m\n' "$*" >&2; exit 1; }
+
+case "$(uname -s)" in
+    Linux) os=linux ;;
+    Darwin) os=macos ;;
+    MINGW* | MSYS* | CYGWIN*)
+        die "On Windows, install WSL2 (wsl --install), open Ubuntu, and run this there." ;;
+    *) die "Unsupported system: $(uname -s). wanderbooks runs on Linux and macOS (Windows via WSL2)." ;;
+esac
+
+# A C compiler: SQLite and a few other pieces are compiled from source.
+if ! command -v cc >/dev/null 2>&1 && ! command -v gcc >/dev/null 2>&1 && ! command -v clang >/dev/null 2>&1; then
+    if [ "$os" = macos ]; then
+        die "Needs Apple's command line tools. Run: xcode-select --install   (then run this again)"
+    fi
+    hint="your distribution's C compiler package"
+    if command -v apt-get >/dev/null 2>&1; then hint="sudo apt-get install -y build-essential"
+    elif command -v dnf >/dev/null 2>&1; then hint="sudo dnf install -y gcc"
+    elif command -v pacman >/dev/null 2>&1; then hint="sudo pacman -S --needed base-devel"
+    elif command -v zypper >/dev/null 2>&1; then hint="sudo zypper install -y gcc"
+    elif command -v apk >/dev/null 2>&1; then hint="sudo apk add build-base"
+    fi
+    die "Needs a C compiler. Run: $hint   (then run this again)"
+fi
+command -v git >/dev/null 2>&1 || die "Needs git. Install it, then run this again."
 
 if ! command -v cargo >/dev/null 2>&1; then
-    say "Installing Rust (rustup)…"
-    curl -fsSL https://sh.rustup.rs | sh -s -- -y --profile minimal
-    # shellcheck disable=SC1091
-    . "$HOME/.cargo/env"
+    if [ -x "$HOME/.cargo/bin/cargo" ]; then
+        PATH="$HOME/.cargo/bin:$PATH"
+    else
+        say "Installing Rust (rustup)…"
+        curl -fsSL https://sh.rustup.rs | sh -s -- -y --profile minimal
+        # shellcheck disable=SC1091
+        . "$HOME/.cargo/env"
+    fi
 fi
 
-say "Installing wanderbooks (a few minutes, once)…"
+say "Installing wanderbooks from $REPO (a few minutes, once)…"
 cargo install --locked --git "$REPO" ledger-cli ledger-mcp ledger-gui
 
 if ! command -v just >/dev/null 2>&1; then
@@ -28,9 +62,14 @@ if ! command -v just >/dev/null 2>&1; then
 fi
 
 if ! command -v claude >/dev/null 2>&1; then
-    say "Claude Code isn't installed: see https://claude.com/claude-code"
+    say "Claude Code isn't installed yet: https://claude.com/claude-code"
 fi
 
+case ":$PATH:" in
+    *":$HOME/.cargo/bin:"*) ;;
+    *) say "Add ~/.cargo/bin to your PATH (rustup's installer usually does; open a new terminal)." ;;
+esac
+
 if [ $# -gt 0 ]; then
     # Hand the terminal to the agent when there is one.
     if [ -t 1 ] && [ -e /dev/tty ]; then