Add guest sessions and agent VM defaults

Add daemon-backed workspace and guest-session primitives so host
orchestrators can prepare /root/repo, launch long-lived guest commands,
and attach to pipe-mode sessions over the local stdio mux bridge.

Persist richer session metadata and launch diagnostics, preflight guest
cwd/command requirements, make pipe-mode attach rehydratable from guest
state after daemon restart, and allow submodules when workspace prepare
runs in full_copy mode.

At the same time, stop vm run from auto-attaching opencode, make it
print next-step commands instead, and make glibc guest images more
agent-ready by installing node, opencode, claude, and pi while syncing
opencode/claude/pi auth files into work disks on VM start.

Validation:
- GOCACHE=/tmp/banger-gocache go test ./...
- make build
- banger vm workspace prepare --help
- banger vm session --help
- banger vm session start --help
- banger vm session attach --help

scripts/customize.sh

@@ -94,6 +94,10 @@ INITRD=""
 MISE_VERSION="v2025.12.0"
 MISE_INSTALL_PATH="/usr/local/bin/mise"
 MISE_ACTIVATE_LINE='eval "$(/usr/local/bin/mise activate bash)"'
+NODE_TOOL="node@22"
+CLAUDE_CODE_PACKAGE="@anthropic-ai/claude-code"
+PI_PACKAGE="@mariozechner/pi-coding-agent"
+NPM_GLOBAL_PREFIX="/root/.local/share/banger/npm-global"
 TMUX_PLUGIN_DIR="/root/.tmux/plugins"
 TMUX_RESURRECT_DIR="/root/.tmux/resurrect"
 TMUX_TPM_REPO="https://github.com/tmux-plugins/tpm"
@@ -399,14 +403,35 @@ fi
 apt-get update
 DEBIAN_FRONTEND=noninteractive apt-get -y upgrade
 DEBIAN_FRONTEND=noninteractive apt-get -y install ${APT_PACKAGES_ESCAPED}
-curl -fsSL https://mise.run | MISE_INSTALL_PATH=\"$MISE_INSTALL_PATH\" MISE_VERSION=\"$MISE_VERSION\" sh
-\"$MISE_INSTALL_PATH\" use -g github:anomalyco/opencode
-\"$MISE_INSTALL_PATH\" reshim
+curl -fsSL https://mise.run | MISE_INSTALL_PATH="$MISE_INSTALL_PATH" MISE_VERSION="$MISE_VERSION" sh
+"$MISE_INSTALL_PATH" use -g "$NODE_TOOL"
+"$MISE_INSTALL_PATH" use -g github:anomalyco/opencode
+"$MISE_INSTALL_PATH" reshim
+if [[ ! -e /root/.local/share/mise/shims/node ]]; then
+  echo 'node shim not found after mise install' >&2
+  exit 1
+fi
+if [[ ! -e /root/.local/share/mise/shims/npm ]]; then
+  echo 'npm shim not found after mise install' >&2
+  exit 1
+fi
 if [[ ! -e /root/.local/share/mise/shims/opencode ]]; then
   echo 'opencode shim not found after mise install' >&2
   exit 1
 fi
+mkdir -p "$NPM_GLOBAL_PREFIX"
+NPM_CONFIG_PREFIX="$NPM_GLOBAL_PREFIX" /root/.local/share/mise/shims/npm install -g "$CLAUDE_CODE_PACKAGE" "$PI_PACKAGE"
+if [[ ! -e "$NPM_GLOBAL_PREFIX/bin/claude" ]]; then
+  echo 'claude binary not found after npm install' >&2
+  exit 1
+fi
+if [[ ! -e "$NPM_GLOBAL_PREFIX/bin/pi" ]]; then
+  echo 'pi binary not found after npm install' >&2
+  exit 1
+fi
 ln -snf /root/.local/share/mise/shims/opencode /usr/local/bin/opencode
+ln -snf "$NPM_GLOBAL_PREFIX/bin/claude" /usr/local/bin/claude
+ln -snf "$NPM_GLOBAL_PREFIX/bin/pi" /usr/local/bin/pi
 mkdir -p /etc/profile.d
 cat > /etc/profile.d/mise.sh <<'MISEPROFILE'
 if [ -n \"\${BASH_VERSION:-}\" ] && [ -x \"$MISE_INSTALL_PATH\" ]; then