Add better documentation and scripts for air-gapped deployment

Created new helper scripts:
- quickstart-airgap.sh: One-command deployment for restricted environments
- check-ready.sh: Validates that pre-built files exist before deployment

Updated documentation:
- Enhanced Dockerfile.frontend.prebuilt with clearer error messages
- Updated DEPLOYMENT.md with step-by-step quick start guide
- Updated README.md to distinguish standard vs air-gapped deployment

Key improvements:
- Clear warning that build must happen BEFORE docker-compose
- Helper script that combines build + deployment steps
- Readiness check to catch missing pre-built files early
- Better instructions for test environments with restricted npm access

This addresses the common error where Docker fails because
frontend/dist/frontend/browser doesn't exist yet.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

DEPLOYMENT.md

@@ -24,12 +24,12 @@ This uses `Dockerfile.frontend` which:
 
 ---
 
-## Option 2: Pre-built Deployment (Air-Gapped/Restricted Environments)
+## Option 2: Pre-built Deployment (Air-Gapped/Restricted Environments) ⭐ RECOMMENDED
 
 Use `Dockerfile.frontend.prebuilt` for environments with restricted npm access.
 
 **Requirements:**
-- Node.js 18+ installed locally
+- Node.js 18+ installed locally (on a machine with npm access)
 - npm installed locally
 - No internet required during Docker build
 
@@ -37,14 +37,34 @@ Use `Dockerfile.frontend.prebuilt` for environments with restricted npm access.
 
 **Usage:**
 
-### Step 1: Build Angular app locally
+### Quick Start (Recommended)
 ```bash
+./quickstart-airgap.sh
+```
+
+This script will:
+1. Build the Angular app locally
+2. Start all Docker containers
+3. Verify the deployment
+
+### Manual Steps
+
+### Step 1: Build Angular app locally
+**IMPORTANT:** You MUST run this step BEFORE `docker-compose up`!
+
+```bash
+# Option A: Use the helper script
+./build-for-airgap.sh
+
+# Option B: Build manually
 cd frontend
 npm install  # Only needed once or when dependencies change
 npm run build:prod
 cd ..
 ```
 
+This creates `frontend/dist/frontend/browser/` which Docker will copy.
+
 ### Step 2: Update docker-compose.yml
 Edit `docker-compose.yml` and change the frontend dockerfile: