Use dynamic npx path detection instead of hardcoded paths

Replace hardcoded /usr/bin/npx and /usr/local/bin/npx with $(which npx)
to handle different npx installation locations.

Co-authored-by: Ona <[email protected]>

Author: jespino

.devcontainer/Dockerfile

@@ -5,8 +5,9 @@ RUN npm config set ignore-scripts true --location=user && \
     echo 'ignore-scripts true' >> ~/.yarnrc
 
 # Disable npx for security
-RUN rm -f /usr/bin/npx /usr/local/bin/npx && \
-    echo '#!/bin/sh' > /usr/local/bin/npx && \
-    echo 'echo "npx is disabled for security reasons. Use explicit package installation instead." >&2' >> /usr/local/bin/npx && \
-    echo 'exit 1' >> /usr/local/bin/npx && \
-    chmod +x /usr/local/bin/npx
+RUN NPX_PATH=$(which npx) && \
+    rm -f "$NPX_PATH" && \
+    echo '#!/bin/sh' > "$NPX_PATH" && \
+    echo 'echo "npx is disabled for security reasons. Use explicit package installation instead." >&2' >> "$NPX_PATH" && \
+    echo 'exit 1' >> "$NPX_PATH" && \
+    chmod +x "$NPX_PATH"