fix: properly stop child processes and orphaned services

- Kill entire process tree (parent + children) when stopping
- Add port-based cleanup as fallback for orphaned processes
- Remove 'set -e' to allow graceful failure handling
- Pass port numbers to stop_service for cleanup

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

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

start.sh

@@ -8,7 +8,7 @@
 #   ./start.sh --status     Show service status
 #   ./start.sh --help       Show help
 
-set -e
+# Note: We don't use 'set -e' here because stop commands may fail gracefully
 
 # Colors
 GREEN='\033[0;32m'
@@ -181,16 +181,47 @@ start_frontend() {
     fi
 }
 
+kill_process_tree() {
+    local pid=$1
+    # Kill all child processes first
+    pkill -TERM -P "$pid" 2>/dev/null || true
+    # Then kill the parent
+    kill -TERM "$pid" 2>/dev/null || true
+}
+
+force_kill_process_tree() {
+    local pid=$1
+    # Force kill all child processes
+    pkill -9 -P "$pid" 2>/dev/null || true
+    # Force kill the parent
+    kill -9 "$pid" 2>/dev/null || true
+}
+
+kill_by_port() {
+    local port=$1
+    local pids=$(lsof -ti :$port 2>/dev/null)
+    if [ -n "$pids" ]; then
+        echo "$pids" | xargs kill -TERM 2>/dev/null || true
+        sleep 1
+        # Force kill if still running
+        pids=$(lsof -ti :$port 2>/dev/null)
+        if [ -n "$pids" ]; then
+            echo "$pids" | xargs kill -9 2>/dev/null || true
+        fi
+    fi
+}
+
 stop_service() {
     local name=$1
     local pid_file=$2
+    local port=$3
 
     if is_running "$pid_file"; then
         local pid=$(get_pid "$pid_file")
         echo -e "${YELLOW}Stopping $name (PID: $pid)...${NC}"
 
-        # Try graceful shutdown first
-        kill -TERM "$pid" 2>/dev/null || true
+        # Kill the entire process tree
+        kill_process_tree "$pid"
 
         # Wait up to 5 seconds
         local count=0
@@ -201,20 +232,28 @@ stop_service() {
 
         # Force kill if still running
         if is_running "$pid_file"; then
-            kill -9 "$pid" 2>/dev/null || true
+            force_kill_process_tree "$pid"
         fi
 
         rm -f "$pid_file"
-        echo -e "${GREEN}$name stopped${NC}"
-    else
-        echo -e "${YELLOW}$name is not running${NC}"
     fi
+
+    # Also kill any orphaned processes by port (fallback)
+    if [ -n "$port" ]; then
+        local port_pids=$(lsof -ti :$port 2>/dev/null)
+        if [ -n "$port_pids" ]; then
+            echo -e "${YELLOW}Cleaning up orphaned processes on port $port...${NC}"
+            kill_by_port "$port"
+        fi
+    fi
+
+    echo -e "${GREEN}$name stopped${NC}"
 }
 
 stop_all() {
     echo -e "${YELLOW}Stopping all services...${NC}"
-    stop_service "Backend" "$BACKEND_PID_FILE"
-    stop_service "Frontend" "$FRONTEND_PID_FILE"
+    stop_service "Backend" "$BACKEND_PID_FILE" "$BACKEND_PORT"
+    stop_service "Frontend" "$FRONTEND_PID_FILE" "$FRONTEND_PORT"
     echo -e "${GREEN}All services stopped${NC}"
 }