Add bare-metal installer and in-app backup/restore

install.sh: no-Docker one-liner for cloud VPS
- Installs Node.js 20 via NodeSource if missing (Ubuntu/Debian/RHEL/Rocky)
- Clones to /opt/capsule, builds, creates a systemd service
- Re-running upgrades in place (git pull + rebuild)

Backup & Restore (Settings → Backup & Restore tab):
- Download Backup: streams all data/ as a .tar.gz (pure Node zlib, no deps)
- Restore: upload a .tar.gz to replace server data, auto sign-out after

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

install.sh

@@ -1,200 +1,141 @@
 #!/bin/bash
-
-# Capsule Budget - One-Line Installer for ZimaOS/Podman/Docker
+# Capsule Budget — bare-metal installer (no Docker)
 # Usage: curl -fsSL https://raw.githubusercontent.com/nmemmert/budget/master/install.sh | bash
 
 set -e
 
 REPO_URL="https://github.com/nmemmert/budget.git"
-INSTALL_DIR="capsule-budget"
+INSTALL_DIR="/opt/capsule"
+SERVICE_USER="capsule"
+PORT=7654
 
-echo "╔════════════════════════════════════════════════════════════╗"
-echo "║                                                            ║"
-echo "║              🌟 Capsule Budget Installer 🌟                ║"
-echo "║                    by NeCloud                              ║"
-echo "║                                                            ║"
-echo "╚════════════════════════════════════════════════════════════╝"
-echo ""
-
-# Check for container engine
-echo "🔍 Checking prerequisites..."
-if command -v podman &> /dev/null; then
-    CONTAINER_ENGINE="podman"
-    echo "✅ Podman found"
-elif command -v docker &> /dev/null; then
-    CONTAINER_ENGINE="docker"
-    echo "✅ Docker found"
-else
-    echo "❌ No supported container engine found"
-    echo "Install Podman (recommended on Rocky Linux) or Docker"
-    exit 1
-fi
-
-# Check for compose command (Podman first)
-if command -v podman-compose &> /dev/null; then
-    CONTAINER_COMPOSE="podman-compose"
-    echo "✅ podman-compose found"
-elif command -v podman &> /dev/null && podman compose version &> /dev/null 2>&1; then
-    CONTAINER_COMPOSE="podman compose"
-    echo "✅ podman compose found"
-elif command -v docker-compose &> /dev/null; then
-    CONTAINER_COMPOSE="docker-compose"
-    echo "✅ docker-compose found"
-elif command -v docker &> /dev/null && docker compose version &> /dev/null 2>&1; then
-    CONTAINER_COMPOSE="docker compose"
-    echo "✅ docker compose found"
-else
-    echo "❌ No supported compose command found"
-    echo "Install one of: podman-compose, podman compose, docker-compose, docker compose"
-    exit 1
-fi
-
-# Check if git is available
-if command -v git &> /dev/null; then
-    USE_GIT=true
-    echo "✅ Git found"
-else
-    USE_GIT=false
-    echo "⚠️  Git not found, will download files directly"
-fi
+RED='\033[0;31m'; GREEN='\033[0;32m'; YELLOW='\033[1;33m'; CYAN='\033[0;36m'; NC='\033[0m'
+ok()   { echo -e "${GREEN}✓${NC} $*"; }
+info() { echo -e "${CYAN}→${NC} $*"; }
+warn() { echo -e "${YELLOW}⚠${NC}  $*"; }
+die()  { echo -e "${RED}✗${NC} $*"; exit 1; }
 
 echo ""
-echo "📦 Installing Capsule Budget..."
+echo "╔══════════════════════════════════════════╗"
+echo "║        Capsule Budget  Installer         ║"
+echo "╚══════════════════════════════════════════╝"
+echo ""
 
-# Remove existing installation if present
-if [ -d "$INSTALL_DIR" ]; then
-    echo "⚠️  Existing installation found"
-    read -p "Do you want to remove it and reinstall? (y/N): " -n 1 -r
-    echo
-    if [[ $REPLY =~ ^[Yy]$ ]]; then
-        echo "🗑️  Removing old installation..."
-        rm -rf "$INSTALL_DIR"
-    else
-        echo "❌ Installation cancelled"
-        exit 0
-    fi
-fi
+# Must be root
+[ "$EUID" -eq 0 ] || die "Run as root: sudo bash install.sh  (or pipe through sudo)"
 
-# Clone or download repository
-if [ "$USE_GIT" = true ]; then
-    echo "📥 Cloning repository..."
-    git clone "$REPO_URL" "$INSTALL_DIR"
+# ── Node.js 20 ────────────────────────────────────────────────────────────────
+install_node() {
+  info "Installing Node.js 20..."
+  if command -v apt-get &>/dev/null; then
+    curl -fsSL https://deb.nodesource.com/setup_20.x | bash -
+    apt-get install -y nodejs
+  elif command -v dnf &>/dev/null; then
+    curl -fsSL https://rpm.nodesource.com/setup_20.x | bash -
+    dnf install -y nodejs
+  elif command -v yum &>/dev/null; then
+    curl -fsSL https://rpm.nodesource.com/setup_20.x | bash -
+    yum install -y nodejs
+  else
+    die "Unsupported package manager. Install Node.js 20 manually then re-run."
+  fi
+}
+
+if command -v node &>/dev/null; then
+  NODE_MAJOR=$(node -e "process.stdout.write(process.versions.node.split('.')[0])")
+  if [ "$NODE_MAJOR" -ge 20 ]; then
+    ok "Node.js $(node --version) already installed"
+  else
+    warn "Node.js $(node --version) is too old (need 20+)"
+    install_node
+  fi
 else
-    echo "📥 Downloading repository..."
-    mkdir -p "$INSTALL_DIR"
-    cd "$INSTALL_DIR"
+  install_node
+fi
+ok "Node.js $(node --version)"
 
-    # Download essential files
-    curl -fsSL "https://raw.githubusercontent.com/nmemmert/budget/master/docker-compose.yml" -o docker-compose.yml
-    curl -fsSL "https://raw.githubusercontent.com/nmemmert/budget/master/Dockerfile" -o Dockerfile
-    curl -fsSL "https://raw.githubusercontent.com/nmemmert/budget/master/.env.example" -o .env.example
-    curl -fsSL "https://raw.githubusercontent.com/nmemmert/budget/master/package.json" -o package.json
+# ── git ───────────────────────────────────────────────────────────────────────
+command -v git &>/dev/null || {
+  info "Installing git..."
+  if command -v apt-get &>/dev/null; then apt-get install -y git
+  elif command -v dnf &>/dev/null;    then dnf install -y git
+  else yum install -y git; fi
+}
+ok "git $(git --version | awk '{print $3}')"
 
-    # Note: Full source code still needs to be downloaded
-    echo "⚠️  For full installation, Git is recommended"
-    echo "Downloading complete source archive..."
-    curl -fsSL "https://github.com/nmemmert/budget/archive/refs/heads/master.tar.gz" | tar -xz --strip-components=1
-    
-    cd ..
+# ── Clone / update ────────────────────────────────────────────────────────────
+if [ -d "$INSTALL_DIR/.git" ]; then
+  info "Updating existing installation at $INSTALL_DIR..."
+  git -C "$INSTALL_DIR" pull --ff-only
+else
+  info "Cloning to $INSTALL_DIR..."
+  git clone "$REPO_URL" "$INSTALL_DIR"
 fi
 
+# ── System user ───────────────────────────────────────────────────────────────
+if ! id "$SERVICE_USER" &>/dev/null; then
+  info "Creating system user '$SERVICE_USER'..."
+  useradd --system --no-create-home --shell /usr/sbin/nologin "$SERVICE_USER"
+fi
+
+# ── Build ─────────────────────────────────────────────────────────────────────
+info "Installing dependencies and building..."
 cd "$INSTALL_DIR"
+npm ci --prefer-offline 2>&1 | tail -3
+npm run build 2>&1 | tail -5
+ok "Build complete"
 
-# Setup environment
-echo ""
-echo "⚙️  Setting up environment..."
+# ── Data directory ────────────────────────────────────────────────────────────
+mkdir -p "$INSTALL_DIR/data"
+chown -R "$SERVICE_USER:$SERVICE_USER" "$INSTALL_DIR"
+ok "Data directory: $INSTALL_DIR/data"
 
-if [ ! -f .env ]; then
-    echo "📝 Creating .env file..."
-    cp .env.example .env
+# ── Systemd service ───────────────────────────────────────────────────────────
+SERVICE_FILE="/etc/systemd/system/capsule.service"
+cat > "$SERVICE_FILE" <<EOF
+[Unit]
+Description=Capsule Budget
+After=network.target
 
-    # Generate encryption key
-    echo "🔑 Generating encryption key..."
+[Service]
+Type=simple
+User=$SERVICE_USER
+WorkingDirectory=$INSTALL_DIR
+ExecStart=$(command -v node) node_modules/.bin/next start -p $PORT
+Restart=on-failure
+RestartSec=5
+Environment=NODE_ENV=production
+Environment=PORT=$PORT
 
-    if command -v openssl &> /dev/null; then
-        # Use openssl if available
-        ENCRYPTION_KEY=$(openssl rand -base64 32)
-    elif [ -r /dev/urandom ]; then
-        # Fallback to /dev/urandom
-        ENCRYPTION_KEY=$(head -c 32 /dev/urandom | base64 | tr -d '\n')
-    else
-        # Last resort: generate from random data
-        ENCRYPTION_KEY=$(cat /dev/random | head -c 32 | base64 | tr -d '\n' 2>/dev/null || echo "PLEASE-CHANGE-THIS-$(date +%s)-$(( RANDOM * RANDOM ))")
-        echo "⚠️  Warning: Could not generate optimal random key"
-        echo "   Please update ENCRYPTION_KEY in .env with a secure random value"
-    fi
+[Install]
+WantedBy=multi-user.target
+EOF
 
-    # Update .env with generated key (escape special chars for sed)
-    ESCAPED_KEY=$(echo "$ENCRYPTION_KEY" | sed 's/[&/\\]/\\&/g')
-    if [[ "$OSTYPE" == "darwin"* ]]; then
-        sed -i '' "s|change-this-to-a-secure-random-key|$ESCAPED_KEY|" .env
-    else
-        sed -i "s|change-this-to-a-secure-random-key|$ESCAPED_KEY|" .env
-    fi
-    echo "✅ Generated secure encryption key"
+systemctl daemon-reload
+systemctl enable capsule
+systemctl restart capsule
+ok "systemd service 'capsule' enabled and started"
+
+# ── Done ──────────────────────────────────────────────────────────────────────
+sleep 2
+if systemctl is-active --quiet capsule; then
+  LOCAL_IP=$(hostname -I 2>/dev/null | awk '{print $1}' || echo "your-server-ip")
+  echo ""
+  echo -e "${GREEN}╔══════════════════════════════════════════╗"
+  echo "║         Installation complete!           ║"
+  echo -e "╚══════════════════════════════════════════╝${NC}"
+  echo ""
+  echo "  Access Capsule at:"
+  echo "    http://$LOCAL_IP:$PORT"
+  echo ""
+  echo "  Useful commands:"
+  echo "    systemctl status capsule      # check status"
+  echo "    systemctl restart capsule     # restart"
+  echo "    journalctl -u capsule -f      # view logs"
+  echo ""
+  echo "  Data lives at: $INSTALL_DIR/data/"
+  echo "  Back up that directory to move to a new server."
+  echo ""
 else
-    echo "ℹ️  .env file already exists, keeping existing configuration"
-fi
-
-# Create data directory
-mkdir -p data
-chmod 0777 data || true
-echo "✅ Data directory created"
-
-# Build and start
-echo ""
-echo "🔨 Building container image..."
-$CONTAINER_COMPOSE build
-
-echo ""
-echo "🚀 Starting Capsule Budget..."
-$CONTAINER_COMPOSE up -d
-
-# Wait for container
-echo "⏳ Waiting for container to start..."
-sleep 5
-
-# Verify container is running
-if $CONTAINER_COMPOSE ps | grep -q "Up"; then
-    echo ""
-    echo "╔════════════════════════════════════════════════════════════╗"
-    echo "║                                                            ║"
-    echo "║           ✅  Installation Complete! ✅                     ║"
-    echo "║                                                            ║"
-    echo "╚════════════════════════════════════════════════════════════╝"
-    echo ""
-    echo "📊 Capsule Budget is running!"
-    echo ""
-    echo "🌐 Access your budget app at:"
-    echo "   • http://localhost:7654"
-    if command -v hostname &> /dev/null; then
-        LOCAL_IP=$(hostname -I 2>/dev/null | awk '{print $1}' || echo "your-device-ip")
-        echo "   • http://$LOCAL_IP:7654"
-    fi
-    echo ""
-    echo "📁 Installation directory: $(pwd)"
-    echo "💾 Data storage: $(pwd)/data"
-    echo ""
-    echo "🔧 Useful commands (run from $(pwd)):"
-    echo "   $CONTAINER_COMPOSE logs -f       # View logs"
-    echo "   $CONTAINER_COMPOSE stop          # Stop Capsule"
-    echo "   $CONTAINER_COMPOSE restart       # Restart Capsule"
-    echo "   $CONTAINER_COMPOSE down          # Stop and remove"
-    echo ""
-    echo "📚 Documentation:"
-    echo "   • README.md - Getting started guide"
-    echo "   • DEPLOYMENT.md - Deployment details"
-    echo ""
-    echo "🎉 Happy budgeting with Capsule!"
-    echo ""
-else
-    echo ""
-    echo "❌ Container failed to start"
-    echo ""
-    echo "Troubleshooting:"
-    echo "1. Check logs: $CONTAINER_COMPOSE logs"
-    echo "2. Verify .env file has ENCRYPTION_KEY set"
-    echo "3. Check if port 7654 is available"
-    echo ""
-    exit 1
+  die "Service failed to start. Check logs: journalctl -u capsule -xe"
 fi

src/app/api/admin/backup/route.ts

@@ -0,0 +1,36 @@
+import { NextRequest, NextResponse } from 'next/server';
+import { FileStorageService } from '@/lib/fileStorage';
+import { buildTarGz } from '@/lib/tarball';
+import path from 'path';
+import fs from 'fs';
+
+const DATA_DIR = path.join(process.cwd(), 'data');
+
+export async function GET(request: NextRequest) {
+  try {
+    const token = request.headers.get('x-session-token');
+    if (!token) return NextResponse.json({ error: 'Unauthorized' }, { status: 401 });
+
+    const session = await FileStorageService.validateSession(token);
+    if (!session) return NextResponse.json({ error: 'Unauthorized' }, { status: 401 });
+
+    if (!fs.existsSync(DATA_DIR)) {
+      return NextResponse.json({ error: 'No data directory found' }, { status: 404 });
+    }
+
+    const timestamp = new Date().toISOString().replace(/[:.]/g, '-').slice(0, 19);
+    const filename = `capsule-backup-${timestamp}.tar.gz`;
+    const body = buildTarGz(DATA_DIR);
+
+    return new NextResponse(body as unknown as BodyInit, {
+      status: 200,
+      headers: {
+        'Content-Type': 'application/gzip',
+        'Content-Disposition': `attachment; filename="${filename}"`,
+        'Content-Length': body.length.toString(),
+      },
+    });
+  } catch (error: any) {
+    return NextResponse.json({ error: error.message || 'Backup failed' }, { status: 500 });
+  }
+}

src/app/api/admin/restore/route.ts

@@ -0,0 +1,37 @@
+import { NextRequest, NextResponse } from 'next/server';
+import { FileStorageService } from '@/lib/fileStorage';
+import { extractTarGz } from '@/lib/tarball';
+import path from 'path';
+import fs from 'fs';
+
+const DATA_DIR = path.join(process.cwd(), 'data');
+
+export async function POST(request: NextRequest) {
+  try {
+    const token = request.headers.get('x-session-token');
+    if (!token) return NextResponse.json({ error: 'Unauthorized' }, { status: 401 });
+
+    const session = await FileStorageService.validateSession(token);
+    if (!session) return NextResponse.json({ error: 'Unauthorized' }, { status: 401 });
+
+    const formData = await request.formData();
+    const file = formData.get('backup') as File | null;
+    if (!file) return NextResponse.json({ error: 'No backup file provided' }, { status: 400 });
+
+    const buffer = Buffer.from(await file.arrayBuffer());
+
+    // Backup current data before overwriting
+    const backupPath = DATA_DIR + '.bak';
+    if (fs.existsSync(DATA_DIR)) {
+      if (fs.existsSync(backupPath)) fs.rmSync(backupPath, { recursive: true });
+      fs.cpSync(DATA_DIR, backupPath, { recursive: true });
+    }
+
+    fs.mkdirSync(DATA_DIR, { recursive: true });
+    await extractTarGz(buffer, DATA_DIR);
+
+    return NextResponse.json({ success: true, message: 'Restore complete. Please sign in again.' });
+  } catch (error: any) {
+    return NextResponse.json({ error: error.message || 'Restore failed' }, { status: 500 });
+  }
+}

src/components/Settings.tsx

@@ -10,7 +10,7 @@ interface SettingsProps {
 }
 
 export default function Settings({ user, onAccountDeleted }: SettingsProps) {
-  const [activeTab, setActiveTab] = useState<'password' | 'export' | 'delete'>('password');
+  const [activeTab, setActiveTab] = useState<'password' | 'export' | 'backup' | 'delete'>('password');
   const [showDeleteConfirm, setShowDeleteConfirm] = useState(false);
   const [showClearDataConfirm, setShowClearDataConfirm] = useState(false);
   const [deleteInput, setDeleteInput] = useState('');
@@ -233,6 +233,69 @@ export default function Settings({ user, onAccountDeleted }: SettingsProps) {
     }
   };
 
+  // ── Backup & Restore ────────────────────────────────────────────────────────
+  const [backupLoading, setBackupLoading] = useState(false);
+  const [restoreLoading, setRestoreLoading] = useState(false);
+  const [backupMessage, setBackupMessage] = useState<{ type: 'success' | 'error'; text: string } | null>(null);
+
+  const handleBackup = async () => {
+    setBackupLoading(true);
+    setBackupMessage(null);
+    try {
+      const token = AuthService.getSessionToken();
+      const res = await fetch('/api/admin/backup', { headers: { 'x-session-token': token ?? '' } });
+      if (!res.ok) { const e = await res.json(); throw new Error(e.error); }
+      const blob = await res.blob();
+      const disposition = res.headers.get('Content-Disposition') ?? '';
+      const match = disposition.match(/filename="([^"]+)"/);
+      const filename = match?.[1] ?? 'capsule-backup.tar.gz';
+      const url = URL.createObjectURL(blob);
+      const a = document.createElement('a');
+      a.href = url; a.download = filename;
+      document.body.appendChild(a); a.click();
+      document.body.removeChild(a); URL.revokeObjectURL(url);
+      setBackupMessage({ type: 'success', text: 'Backup downloaded successfully.' });
+    } catch (e: any) {
+      setBackupMessage({ type: 'error', text: e.message || 'Backup failed' });
+    } finally {
+      setBackupLoading(false);
+    }
+  };
+
+  const handleRestore = async (e: React.ChangeEvent<HTMLInputElement>) => {
+    const file = e.target.files?.[0];
+    if (!file) return;
+    if (!file.name.endsWith('.tar.gz') && !file.name.endsWith('.tgz')) {
+      setBackupMessage({ type: 'error', text: 'File must be a .tar.gz backup.' });
+      return;
+    }
+    if (!confirm('This will replace ALL server data with the backup. Are you sure?')) {
+      e.target.value = '';
+      return;
+    }
+    setRestoreLoading(true);
+    setBackupMessage(null);
+    try {
+      const token = AuthService.getSessionToken();
+      const form = new FormData();
+      form.append('backup', file);
+      const res = await fetch('/api/admin/restore', {
+        method: 'POST',
+        headers: { 'x-session-token': token ?? '' },
+        body: form,
+      });
+      const data = await res.json();
+      if (!res.ok) throw new Error(data.error);
+      setBackupMessage({ type: 'success', text: data.message });
+      setTimeout(() => AuthService.signOut(), 3000);
+    } catch (e: any) {
+      setBackupMessage({ type: 'error', text: e.message || 'Restore failed' });
+    } finally {
+      setRestoreLoading(false);
+      e.target.value = '';
+    }
+  };
+
   const handleClearData = async () => {
     if (clearDataInput !== 'CLEAR ALL' || !showClearDataConfirm) return;
 
@@ -269,6 +332,7 @@ export default function Settings({ user, onAccountDeleted }: SettingsProps) {
           {[
             { id: 'password', label: 'Password & Security' },
             { id: 'export', label: 'Data & Export' },
+            { id: 'backup', label: 'Backup & Restore' },
             { id: 'delete', label: 'Account' },
           ].map((tab) => (
             <button
@@ -501,6 +565,44 @@ export default function Settings({ user, onAccountDeleted }: SettingsProps) {
         </div>
       )}
 
+      {/* Backup & Restore Tab */}
+      {activeTab === 'backup' && (
+        <div className="space-y-6 max-w-md">
+          {backupMessage && (
+            <div className={`p-3 rounded-lg text-sm ${backupMessage.type === 'success' ? 'bg-green-50 text-green-800 border border-green-200' : 'bg-red-50 text-red-800 border border-red-200'}`}>
+              {backupMessage.text}
+            </div>
+          )}
+
+          {/* Backup */}
+          <div className="bg-white rounded-lg shadow-sm border p-6">
+            <h3 className="text-lg font-semibold text-gray-900 mb-1">Download Backup</h3>
+            <p className="text-sm text-gray-500 mb-4">
+              Downloads a <code>.tar.gz</code> archive of all server data — accounts, transactions, users, and sessions. Use this to migrate to a new server.
+            </p>
+            <button onClick={handleBackup} disabled={backupLoading}
+              className="w-full bg-blue-600 text-white py-2 px-4 rounded-md hover:bg-blue-700 disabled:opacity-50 transition-opacity text-sm font-medium">
+              {backupLoading ? 'Creating backup…' : 'Download Backup'}
+            </button>
+          </div>
+
+          {/* Restore */}
+          <div className="bg-white rounded-lg shadow-sm border p-6">
+            <h3 className="text-lg font-semibold text-gray-900 mb-1">Restore from Backup</h3>
+            <p className="text-sm text-gray-500 mb-1">
+              Upload a backup file to restore all data. <strong>This replaces everything on this server.</strong>
+            </p>
+            <p className="text-xs text-amber-700 bg-amber-50 border border-amber-200 rounded px-3 py-2 mb-4">
+              You will be signed out automatically after a successful restore.
+            </p>
+            <label className={`flex items-center justify-center w-full py-2 px-4 rounded-md text-sm font-medium cursor-pointer transition-opacity ${restoreLoading ? 'bg-gray-300 text-gray-500 pointer-events-none' : 'bg-amber-600 hover:bg-amber-700 text-white'}`}>
+              {restoreLoading ? 'Restoring…' : 'Choose Backup File…'}
+              <input type="file" accept=".tar.gz,.tgz" onChange={handleRestore} className="hidden" disabled={restoreLoading} />
+            </label>
+          </div>
+        </div>
+      )}
+
       {/* Delete Tab */}
       {activeTab === 'delete' && (
         <div className="bg-red-50 border border-red-200 rounded-lg p-6 max-w-md">

src/lib/tarball.ts

@@ -0,0 +1,88 @@
+import fs from 'fs';
+import path from 'path';
+import zlib from 'zlib';
+
+// Minimal tar builder (POSIX ustar) — no deps
+function encodeHeader(name: string, size: number): Buffer {
+  const h = Buffer.alloc(512, 0);
+  const write = (val: string, offset: number, len: number) =>
+    h.write(val.slice(0, len), offset, 'ascii');
+
+  write(name.slice(0, 99), 0, 100);       // name
+  write('0000644\0', 100, 8);             // mode
+  write('0000000\0', 108, 8);             // uid
+  write('0000000\0', 116, 8);             // gid
+  write(size.toString(8).padStart(11, '0') + '\0', 124, 12); // size
+  write(Math.floor(Date.now() / 1000).toString(8).padStart(11, '0') + '\0', 136, 12); // mtime
+  h.write('        ', 148, 8, 'ascii');   // checksum placeholder
+  h[156] = 0x30;                          // type '0' = regular file
+  write('ustar\0', 257, 6);
+  write('00', 263, 2);
+
+  let ck = 0;
+  for (let i = 0; i < 512; i++) ck += h[i];
+  h.write(ck.toString(8).padStart(6, '0') + '\0 ', 148, 8, 'ascii');
+
+  return h;
+}
+
+function walkDir(dir: string): string[] {
+  const results: string[] = [];
+  for (const entry of fs.readdirSync(dir, { withFileTypes: true })) {
+    const full = path.join(dir, entry.name);
+    if (entry.isDirectory()) results.push(...walkDir(full));
+    else if (entry.isFile()) results.push(full);
+  }
+  return results;
+}
+
+export function buildTarGz(sourceDir: string): Buffer {
+  const files = walkDir(sourceDir);
+  const blocks: Buffer[] = [];
+
+  for (const file of files) {
+    const content = fs.readFileSync(file);
+    const relName = 'data/' + path.relative(sourceDir, file);
+    blocks.push(encodeHeader(relName, content.length));
+    // file content padded to 512-byte boundary
+    const padded = Buffer.alloc(Math.ceil(content.length / 512) * 512, 0);
+    content.copy(padded);
+    blocks.push(padded);
+  }
+
+  // two 512-byte zero blocks = end of archive
+  blocks.push(Buffer.alloc(1024, 0));
+
+  const tar = Buffer.concat(blocks);
+  return zlib.gzipSync(tar);
+}
+
+export async function extractTarGz(buffer: Buffer, destDir: string): Promise<void> {
+  const tar = zlib.gunzipSync(buffer);
+  let offset = 0;
+
+  while (offset + 512 <= tar.length) {
+    const header = tar.slice(offset, offset + 512);
+    offset += 512;
+
+    // All-zero block = end of archive
+    if (header.every(b => b === 0)) break;
+
+    const name = header.toString('ascii', 0, 100).replace(/\0/g, '').trim();
+    const size = parseInt(header.toString('ascii', 124, 136).trim(), 8) || 0;
+    const type = String.fromCharCode(header[156]);
+
+    const dataBlocks = Math.ceil(size / 512) * 512;
+
+    if (type === '0' || type === '\0') {
+      // Strip leading 'data/' prefix and resolve inside destDir
+      const rel = name.replace(/^data\//, '');
+      if (!rel) { offset += dataBlocks; continue; }
+      const dest = path.join(destDir, rel);
+      fs.mkdirSync(path.dirname(dest), { recursive: true });
+      fs.writeFileSync(dest, tar.slice(offset, offset + size));
+    }
+
+    offset += dataBlocks;
+  }
+}