Update devcontainer (AI+human)

.devcontainer/Dockerfile

@@ -7,37 +7,35 @@
 #   - CMake + Ninja for the build system
 #   - xorriso and mtools used internally by grub-mkrescue / grub-mkimage
 
-FROM debian:bookworm-slim
+FROM alpine:3.23
 
-ENV DEBIAN_FRONTEND=noninteractive
-
-RUN apt-get update && apt-get install -y --no-install-recommends \
+RUN apk add --no-cache \
     # Core build tools
     clang \
     lld \
     cmake \
-    ninja-build \
+    ninja \
     make \
     git \
     # GRUB image generation
-    grub-pc-bin \
-    grub-common \
+    grub \
     xorriso \
     mtools \
     # QEMU for running the OS
-    qemu-system-x86 \
+    qemu-system-i386 \
     # Handy utilities
     file \
-    ca-certificates \
-    && rm -rf /var/lib/apt/lists/*
+    ca-certificates
 
 # Verify the cross-compilation toolchain can produce an i386-elf binary.
+# Compile and link separately so ld.lld is invoked directly, avoiding the
+# host gcc linker driver (which rejects -m32 on non-x86 hosts such as aarch64).
 RUN echo 'void _start(void){for(;;)__asm__("hlt");}' > /tmp/test.c \
-    && clang -target i386-elf -m32 -march=i386 -ffreestanding -fno-stack-protector \
-             -nostdlib -fuse-ld=lld -Wl,-e,_start \
-             /tmp/test.c -o /tmp/test.elf \
-    && file /tmp/test.elf | grep -q "ELF 32-bit.*80386" \
+    && clang -v -target i386-elf -march=i386 -ffreestanding -fno-stack-protector \
+             -c /tmp/test.c -o /tmp/test.o \
+    && ld.lld -m elf_i386 -e _start --nostdlib /tmp/test.o -o /tmp/test.elf \
+    && file /tmp/test.elf | grep -q "ELF 32-bit.*386" \
     && echo "Toolchain OK" \
-    && rm /tmp/test.c /tmp/test.elf
+    && rm /tmp/test.c /tmp/test.o /tmp/test.elf
 
 WORKDIR /workspaces/claude-os