enhance GRBLHandler response handling; raise error on missing response and add delay for command processing

robot-control/src/api/grbl_handler.py

@@ -60,7 +60,8 @@ class GRBLHandler:
                 logger.debug(f"Sending G-Code command: {cmd}")
                 self.writer.write(f"{cmd}\n".encode())
                 await self.writer.drain()
-                await self._process_response()
+                if not (await self._process_response()):
+                    raise RuntimeError("Did not receive response from GRBL")
         except RuntimeError as e:
             logger.error(f"Failed to send G-Code commands: {str(e)}")
         finally:
@@ -77,7 +78,9 @@ class GRBLHandler:
             if self.writer:
                 self.writer.write(b"?\n")
                 await self.writer.drain()
+                # '?' command returns status report and 'ok'
                 response = await self._process_response()
+                response = response + await self._process_response()
                 
                 if response and "Idle" in response:
                     logger.debug("Movement complete.\nContinuing...")
@@ -93,6 +96,7 @@ class GRBLHandler:
     async def send_and_wait_gcode(self, commands: List[str], timeout_s=60):
         """Send GCODE commands and wait until machine is idle"""
         await self.send_gcode(commands)
+        await asyncio.sleep(0.2)  # Delay to allow GRBL to process commands
         await self.wait_until_idle(timeout_s)
 
     async def _process_response(self):