Add start/stop/restart scripts and USER_GUIDE documentation

start.sh

@@ -0,0 +1,34 @@
+#!/usr/bin/env bash
+# Start script for AI Job Application server
+
+APP_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+PID_FILE="$APP_DIR/.app.pid"
+LOG_FILE="$APP_DIR/.app.log"
+
+if [ -f "$PID_FILE" ]; then
+    PID=$(cat "$PID_FILE")
+    if kill -0 "$PID" 2>/dev/null; then
+        echo "AI Job Application server is already running (PID: $PID)."
+        echo "Access it at http://localhost:3000"
+        exit 0
+    else
+        rm -f "$PID_FILE"
+    fi
+fi
+
+echo "Starting AI Job Application server..."
+cd "$APP_DIR" || exit 1
+nohup npm run dev > "$LOG_FILE" 2>&1 &
+SERVER_PID=$!
+echo "$SERVER_PID" > "$PID_FILE"
+
+sleep 2
+if kill -0 "$SERVER_PID" 2>/dev/null; then
+    echo "✓ Server successfully started (PID: $SERVER_PID)."
+    echo "✓ App running at: http://localhost:3000"
+    echo "✓ Logs: $LOG_FILE"
+else
+    echo "❌ Server failed to start. Check logs at $LOG_FILE"
+    rm -f "$PID_FILE"
+    exit 1
+fi