fix(container): remove separate cargo package (included in rust on wolfi)

Chainguard wolfi-base bundles cargo with the rust package. The
separate 'cargo' apk doesn't exist, causing the container build
to fail.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: hyperpolymath

Containerfile

@@ -28,7 +28,6 @@ FROM cgr.dev/chainguard/wolfi-base:latest AS rust-builder
 
 RUN apk add --no-cache \
     rust \
-    cargo \
     build-base \
     pkgconf \
     openssl-dev