Fix Dockerfiles: use local start-chromium.sh instead of non-existent submodule version

The kernel-images submodule doesn't contain start-chromium.sh.
All deployment types use custom patched versions in deployments/*/scripts/.

Changes:
- deployments/local/Dockerfile: Remove duplicate COPY from submodule
- deployments/local-webarena/Dockerfile: Remove duplicate COPY from submodule
- deployments/cloudrun/Dockerfile: Use local scripts/start-chromium.sh

This fixes the build error:
  failed to compute cache key: start-chromium.sh: not found

Author: olesho

deployments/cloudrun/Dockerfile

@@ -256,8 +256,11 @@ COPY --from=xorg-deps /usr/local/lib/xorg/modules/drivers/dummy_drv.so /usr/lib/
 COPY --from=xorg-deps /usr/local/lib/xorg/modules/input/neko_drv.so /usr/lib/xorg/modules/input/neko_drv.so
 
 COPY submodules/kernel-images/images/chromium-headful/image-chromium/ /
-COPY submodules/kernel-images/images/chromium-headful/start-chromium.sh /images/chromium-headful/start-chromium.sh
+
+# Copy custom start-chromium.sh with patches
+COPY deployments/cloudrun/scripts/start-chromium.sh /images/chromium-headful/start-chromium.sh
 RUN chmod +x /images/chromium-headful/start-chromium.sh
+
 COPY submodules/kernel-images/images/chromium-headful/supervisord.conf /etc/supervisor/supervisord.conf
 COPY deployment/cloudrun/supervisord-cloudrun.conf /etc/supervisor/supervisord-cloudrun.conf
 COPY submodules/kernel-images/images/chromium-headful/supervisor/services/ /etc/supervisor/conf.d/services/

deployments/local-webarena/Dockerfile

@@ -201,8 +201,6 @@ COPY --from=xorg-deps /usr/local/lib/xorg/modules/drivers/dummy_drv.so /usr/lib/
 COPY --from=xorg-deps /usr/local/lib/xorg/modules/input/neko_drv.so /usr/lib/xorg/modules/input/neko_drv.so
 
 COPY submodules/kernel-images/images/chromium-headful/image-chromium/ /
-COPY submodules/kernel-images/images/chromium-headful/start-chromium.sh /images/chromium-headful/start-chromium.sh
-RUN chmod +x /images/chromium-headful/start-chromium.sh
 COPY submodules/kernel-images/images/chromium-headful/wrapper.sh /wrapper.sh
 COPY submodules/kernel-images/images/chromium-headful/supervisord.conf /etc/supervisor/supervisord.conf
 COPY submodules/kernel-images/images/chromium-headful/supervisor/services/ /etc/supervisor/conf.d/services/

deployments/local/Dockerfile

@@ -201,8 +201,6 @@ COPY --from=xorg-deps /usr/local/lib/xorg/modules/drivers/dummy_drv.so /usr/lib/
 COPY --from=xorg-deps /usr/local/lib/xorg/modules/input/neko_drv.so /usr/lib/xorg/modules/input/neko_drv.so
 
 COPY submodules/kernel-images/images/chromium-headful/image-chromium/ /
-COPY submodules/kernel-images/images/chromium-headful/start-chromium.sh /images/chromium-headful/start-chromium.sh
-RUN chmod +x /images/chromium-headful/start-chromium.sh
 COPY submodules/kernel-images/images/chromium-headful/wrapper.sh /wrapper.sh
 COPY submodules/kernel-images/images/chromium-headful/supervisord.conf /etc/supervisor/supervisord.conf
 COPY submodules/kernel-images/images/chromium-headful/supervisor/services/ /etc/supervisor/conf.d/services/