✨ Build rust image with full toolchain, workflow, and utilities ✨

Install latest stable Rust at build time via rustup-init with SHA256
verification. Add 30 cross-compile targets, cargo-binstall, and a
comprehensive set of cargo development tools. Match the official
rust:alpine env-var convention (RUSTUP_HOME / CARGO_HOME) and declare
those paths as Docker VOLUMEs. Add the Go-image pattern: rust-workflow
runs automatically when the container is invoked with no args, while
explicit commands pass through unchanged. Copy language-agnostic
healthcheck, copy, and symlink utilities from the Go image.
- Dockerfile: WORKDIR /app in final stage; add RUSTUP_HOME, CARGO_HOME,
RUSTUP_TOOLCHAIN ENV vars; extend VOLUME to include cargo and rustup paths
- rootfs/root/docker/setup/05-custom.sh: full Rust toolchain install —
build deps (build-base musl-dev clang lld cmake openssl-dev), SHA256-
verified rustup-init, stable toolchain with rust-src/rust-analyzer/
llvm-tools-preview, 30 cross-compile targets, cargo-binstall bootstrap,
cargo tool suite via binstall, cross-linker config.toml, /usr/local/bin
symlinks, ~/.cargo and ~/.rustup home symlinks, /etc/profile.d/rust.sh
- rootfs/usr/local/bin/rust-workflow: default workflow script —
fmt --check → clippy -D warnings → test --all → build --release;
honours CARGO_WORKDIR and CARGO_BUILD_TARGET env vars
- rootfs/usr/local/bin/entrypoint.sh: __no_exit guarded by $# -eq 0 in
START_SERVICES block; * catch-all now calls rust-workflow on no args
- rootfs/usr/local/bin/healthcheck: copied from Go image (HTTP/TCP/
process/file health probe)
- rootfs/usr/local/bin/copy: copied from Go image (recursive copy utility)
- rootfs/usr/local/bin/symlink: copied from Go image (symlink utility)

Dockerfile
rootfs/root/docker/setup/05-custom.sh
rootfs/usr/local/bin/copy
rootfs/usr/local/bin/entrypoint.sh
rootfs/usr/local/bin/healthcheck
rootfs/usr/local/bin/rust-workflow
rootfs/usr/local/bin/symlink

rootfs/usr/local/bin/entrypoint.sh

@@ -506,9 +506,11 @@ if [ "$START_SERVICES" = "yes" ] || [ -z "$1" ]; then
     echo "$$" >"$ENTRYPOINT_PID_FILE"
     __start_init_scripts "/usr/local/etc/docker/init.d"
     CONTAINER_INIT="${CONTAINER_INIT:-no}"
-    # Services started successfully - enter monitoring mode
-    __no_exit
-    exit $?
+    # Only block in monitoring mode when no user command was given
+    if [ $# -eq 0 ]; then
+      __no_exit
+      exit $?
+    fi
   fi
   START_SERVICES="no"
 fi
@@ -674,11 +676,8 @@ start)
 # Execute primary command
 *)
   if [ $# -eq 0 ]; then
-    if [ ! -f "$ENTRYPOINT_PID_FILE" ]; then
-      echo "$$" >"$ENTRYPOINT_PID_FILE"
-      [ "$START_SERVICES" = "no" ] && [ "$CONTAINER_INIT" = "yes" ] || __start_init_scripts "/usr/local/etc/docker/init.d"
-    fi
-    __no_exit
+    # No args: run the default Rust workflow (fmt → clippy → test → build)
+    __exec_command rust-workflow
   else
     __exec_command "$@"
   fi