fix: make CARGO_HOME world-writable so user 1000 can build crates

cargo needs to write to /usr/local/cargo/registry when downloading
crate sources. chmod a+rx was missing the write bit, causing
'Permission denied' on registry/cache/ during tokenizers wheel build.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: dvystrcil

Dockerfile

@@ -25,7 +25,7 @@ RUN apt-get update && \
     && rm -rf /var/lib/apt/lists/* \
     && curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | \
        sh -s -- -y --default-toolchain stable --no-modify-path \
-    && chmod -R a+rx /usr/local/rustup /usr/local/cargo \
+    && chmod -R a+rwx /usr/local/rustup /usr/local/cargo \
     && curl -sL "https://github.com/oras-project/oras/releases/download/v${ORAS_VERSION}/oras_${ORAS_VERSION}_linux_amd64.tar.gz" \
        | tar -xz -C /usr/local/bin oras