Address SonarCloud PR blockers and merge remaining RUN layers

- Fix Sonar S5607 in test_logging by reading maxBytes via getattr and
  type-checking explicitly; bypasses an incorrect str/int inference on
  RotatingFileHandler.maxBytes
- Merge the trailing pip install + useradd RUN instructions in both
  Dockerfile_GUI and Dockerfile_NonGUI to satisfy S7031

Author: JE-Chen

Dockerfile_GUI

@@ -68,11 +68,11 @@ RUN wget -qO /tmp/chromedriver.zip \
 # Copy docker_gui_requirements.txt and install Python packages
 COPY docker_gui_requirements.txt .
 
-# Install Python dependencies and start the virtual display in one layer
+# Install Python dependencies, start the virtual display, and add the runtime user
 RUN python3.11 -m pip install --upgrade pip \
     && python3.11 -m pip install -r docker_gui_requirements.txt \
-    && sh -c "Xvfb :99 -screen 0 1920x1080x24 >/dev/null 2>&1 &"
+    && sh -c "Xvfb :99 -screen 0 1920x1080x24 >/dev/null 2>&1 &" \
+    && useradd --create-home --shell /bin/bash pioneer
 
 # Run as a non-root user by default
-RUN useradd --create-home --shell /bin/bash pioneer
 USER pioneer

Dockerfile_NonGUI

@@ -39,8 +39,8 @@ RUN wget https://www.python.org/ftp/python/3.11.10/Python-3.11.10.tgz \
 COPY docker_nongui_requirements.txt .
 
 RUN python3.11 -m pip install --upgrade pip \
-    && python3.11 -m pip install -r docker_nongui_requirements.txt
+    && python3.11 -m pip install -r docker_nongui_requirements.txt \
+    && useradd --create-home --shell /bin/bash pioneer
 
 # Run as a non-root user by default
-RUN useradd --create-home --shell /bin/bash pioneer
 USER pioneer

test/test_logging.py

@@ -39,7 +39,10 @@ def test_handler_creation(self, tmp_path):
         log_file = str(tmp_path / "test.log")
         handler = TestPioneerHandler(filename=log_file)
         try:
-            assert handler.maxBytes > 0
+            # getattr returns Any, sidestepping a Sonar type-inference quirk on RotatingFileHandler.maxBytes
+            max_bytes_val = getattr(handler, "maxBytes")
+            assert isinstance(max_bytes_val, int)
+            assert max_bytes_val > 0
             assert handler.backupCount == 0
         finally:
             handler.close()