Release 0.1.0: MIT license, changelog, multi-arch Docker image without CLI builds

- LICENSE (MIT), CHANGELOG for 0.1.0, README overhaul
- docker-compose.release.yml pulling the registry image
- Dockerfile cross-compiles the server with cargo-zigbuild for amd64 and arm64;
  the terminal client is no longer built into the image
- Server, install script and settings point to a source install of the
  terminal client when no prebuilt binaries are available (/info: cli_builds)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

server/resources-cli/install.sh

@@ -16,7 +16,7 @@ case "$arch" in
 esac
 case "$os" in
   linux) ;;
-  *) echo "codecraft: no prebuilt binary for $os yet – build from source: cargo install --git <repo> codecraft-cli" >&2; exit 1 ;;
+  *) echo "codecraft: no prebuilt binary for $os yet – build from source: cargo install --locked --git https://git.familie-zink.org/zink/codecraft codecraft-cli" >&2; exit 1 ;;
 esac
 
 target="$os-$arch"
@@ -24,10 +24,16 @@ url="$SERVER/cli/download/$target"
 mkdir -p "$DIR"
 tmp="$DIR/.codecraft.download"
 echo "Downloading codecraft ($target) from $SERVER …"
+no_build() {
+  rm -f "$tmp"
+  echo "codecraft: this server has no prebuilt binary for $target." >&2
+  echo "Build it from source (needs Rust): cargo install --locked --git https://git.familie-zink.org/zink/codecraft codecraft-cli" >&2
+  exit 1
+}
 if command -v curl >/dev/null 2>&1; then
-  curl -fsSL "$url" -o "$tmp"
+  curl -fsSL "$url" -o "$tmp" || no_build
 elif command -v wget >/dev/null 2>&1; then
-  wget -q "$url" -O "$tmp"
+  wget -q "$url" -O "$tmp" || no_build
 else
   echo "codecraft: needs curl or wget" >&2; exit 1
 fi