Add auto-populate eyes on startup and comprehensive .env docs

- Create entrypoint.sh that auto-downloads sample eyes on first run
- Update Dockerfile to use entrypoint script
- Rewrite .env.example with step-by-step setup instructions
- Add detailed troubleshooting section
- Clarify which models work for inpainting vs text-to-image

backend/entrypoint.sh

@@ -0,0 +1,38 @@
+#!/bin/bash
+# =============================================================================
+# AI Photo Edit - Container Startup Script
+# =============================================================================
+# This script runs when the container starts. It:
+# 1. Downloads sample eye images if the catalog is empty
+# 2. Ensures all directories exist
+# 3. Starts the FastAPI server
+# =============================================================================
+
+set -e
+
+echo "=========================================="
+echo "AI Photo Edit - Starting Up"
+echo "=========================================="
+
+# Ensure data directories exist
+mkdir -p /app/data/projects
+mkdir -p /app/data/patches
+mkdir -p /app/data/models
+
+# Check if eye catalog needs to be populated
+echo "Checking eye catalog..."
+PATCHES_COUNT=$(find /app/data/patches -maxdepth 1 -type d | wc -l)
+
+if [ "$PATCHES_COUNT" -le 1 ]; then
+    echo "Eye catalog is empty. Downloading sample eyes..."
+    python /scripts/download_sample_eyes.py || echo "Warning: Could not download sample eyes (non-fatal)"
+else
+    echo "Eye catalog has content, skipping download."
+fi
+
+echo "=========================================="
+echo "Starting FastAPI server..."
+echo "=========================================="
+
+# Start the server
+exec uvicorn app.main:app --host 0.0.0.0 --port 8000