fix: enable MLX CPU inference on x86_64 Linux in Docker

Two issues prevented MLX CPU from working on x86_64 in Docker:

1. Missing BLAS/LAPACK libraries: MLX CPU backend requires libblas-dev,
   liblapack-dev, and liblapacke-dev on Linux. Added to apt-get install.

2. g++ wrapper ordering: The -fpermissive wrapper for GCC 14 was installed
   AFTER uv sync, but MLX may compile extensions during install. Moved
   the wrapper BEFORE uv sync so both build-time and runtime JIT
   compilation benefit from the fix.

MLX publishes manylinux_2_35_x86_64 wheels, so this uses the native
CPU backend — no alternative inference framework needed.

Co-Authored-By: Claude Opus 4.6 <[email protected]>

e2e/Dockerfile

@@ -10,10 +10,14 @@ RUN npm run build
 FROM python:3.13-slim
 
 # Install system dependencies
+# libblas-dev/liblapack-dev/liblapacke-dev are required by MLX CPU backend on Linux
 RUN apt-get update && apt-get install -y \
     build-essential \
     pkg-config \
     libssl-dev \
+    libblas-dev \
+    liblapack-dev \
+    liblapacke-dev \
     curl \
     protobuf-compiler \
     iptables \
@@ -23,6 +27,13 @@ RUN apt-get update && apt-get install -y \
 RUN curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- -y --default-toolchain nightly
 ENV PATH="/root/.cargo/bin:${PATH}"
 
+# Wrap g++ with -fpermissive to fix MLX CPU JIT compilation with GCC 14
+# (GCC 14 treats _Float128/_Float32/_Float64 as built-in types, conflicting with MLX-generated code)
+# Must be done BEFORE uv sync so any source builds also get the fix
+RUN mv /usr/bin/g++ /usr/bin/g++.real && \
+    printf '#!/bin/sh\nexec /usr/bin/g++.real -fpermissive "$@"\n' > /usr/bin/g++ && \
+    chmod +x /usr/bin/g++
+
 # Install uv
 COPY --from=ghcr.io/astral-sh/uv:latest /uv /usr/local/bin/uv
 
@@ -44,10 +55,4 @@ COPY --from=dashboard /app/dashboard/build ./dashboard/build/
 # to keep the layer small (Rust target/ and cargo registry can be 1-2 GB)
 RUN uv sync && rm -rf /app/rust/target /root/.cargo/registry /root/.cargo/git
 
-# Wrap g++ with -fpermissive to fix MLX CPU JIT compilation with GCC 14
-# (GCC 14 treats _Float128/_Float32/_Float64 as built-in types, conflicting with MLX-generated code)
-RUN mv /usr/bin/g++ /usr/bin/g++.real && \
-    printf '#!/bin/sh\nexec /usr/bin/g++.real -fpermissive "$@"\n' > /usr/bin/g++ && \
-    chmod +x /usr/bin/g++
-
 CMD [".venv/bin/exo", "-v"]