feat: migrate all container images to Archipelago app registry

All container image references now pull from 80.71.235.15:3000/archipelago/
instead of Docker Hub and ghcr.io. image-versions.sh is the single source
of truth; all scripts use $*_IMAGE variables instead of hardcoded refs.

Files updated:
- scripts/image-versions.sh: central ARCHY_REGISTRY variable
- core/*/config.rs: registry whitelist includes app registry
- core/*/stacks.rs: Immich + Penpot stack images
- scripts/{first-boot,deploy-to-target,container-specs}.sh: use variables
- docker/*/Dockerfile: nginx base image from registry
- image-recipe/: ISO build, podman config, menu script
- scripts/{container-doctor,deploy-bitcoin-knots,fix-indeedhub,validate-app-manifest}.sh

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

scripts/deploy-bitcoin-knots.sh

@@ -52,7 +52,7 @@ podman run -d \
   --label "com.archipelago.icon=/assets/img/app-icons/bitcoin-knots.webp" \
   --label "com.archipelago.port=8332" \
   --label "com.archipelago.repo=https://github.com/bitcoinknots/bitcoin" \
-  "${BITCOIN_KNOTS_IMAGE:-docker.io/bitcoinknots/bitcoin:v28.1}" \
+  "${BITCOIN_KNOTS_IMAGE}" \
   -server=1 \
   -txindex=1 \
   -rpcallowip=127.0.0.1/32 -rpcallowip=10.88.0.0/16 \
@@ -74,7 +74,7 @@ mkdir -p "$BUILD_DIR"
 
 # Create Dockerfile
 cat > "$BUILD_DIR/Dockerfile" << 'EOF'
-FROM docker.io/library/nginx:alpine
+FROM ${NGINX_ALPINE_IMAGE:-80.71.235.15:3000/archipelago/nginx:1.29.6-alpine}
 
 # Copy the static UI
 COPY index.html /usr/share/nginx/html/