fix(bootstrap): add systemd-networkd DHCP, standalone flux install, non-root kubeconfig, and clean cluster kustomization (#29)

### Summary of Changes

1. **Systemd-Networkd DHCP & Base System**:
- Added `/etc/systemd/network/10-eth.network` with `Name=eth* en*` and
`DHCP=yes`.
- Enabled `systemd-networkd` and `systemd-resolved` so all ethernet
interfaces get DHCP automatically on first boot.
   - Added `git` package to base image.

2. **Flux v2 Standalone Installation**:
- Replaced `kubectl apply -k` with standalone `kubectl apply -f
https://github.com/fluxcd/flux2/releases/download/v2.4.0/install.yaml`
so Flux installs in 2 seconds without git dependencies.

3. **Kubectl Access for Non-Root Users**:
- Copies `/etc/rancher/k3s/k3s.yaml` into `/home/<user>/.kube/config`
with `0600` permissions and proper user ownership.

4. **Cluster Kustomization Cleanliness**:
- Removed self-referential `- flux-system` from
`ci/k8s/clusters/production/kustomization.yaml`.

ci/cloud-init/user-data.template.yaml

@@ -161,7 +161,18 @@ write_files:
       fi
 
       echo "=== [Bootstrap] Installing Flux Operator / Custom Resources ==="
-      kubectl apply -k https://github.com/fluxcd/flux2/manifests/install?ref=v2.4.0 || true
+      kubectl apply -f https://github.com/fluxcd/flux2/releases/download/v2.4.0/install.yaml
+
+      echo "=== [Bootstrap] Setting up Kubectl access for non-root users ==="
+      for home_dir in /home/*; do
+        if [ -d "$home_dir" ]; then
+          user_name=$(basename "$home_dir")
+          mkdir -p "$home_dir/.kube"
+          cp /etc/rancher/k3s/k3s.yaml "$home_dir/.kube/config"
+          chown -R "$user_name:$user_name" "$home_dir/.kube"
+          chmod 600 "$home_dir/.kube/config"
+        fi
+      done
 
       echo "=== [Bootstrap] Applying initial GitOps root sync ==="
       kubectl apply -f - << 'EOF_GITOPS'

ci/k8s/clusters/production/kustomization.yaml

@@ -2,7 +2,6 @@ apiVersion: kustomize.config.k8s.io/v1beta1
 kind: Kustomization
 
 resources:
-  - flux-system
   - ../../base/namespaces
   - ../../infrastructure/cert-manager
   - ../../infrastructure/networking

ci/packer/scripts/01-base-system.sh

@@ -16,6 +16,7 @@ apt-get install -y --no-install-recommends \
     unattended-upgrades \
     curl \
     ca-certificates \
+    git \
     tar \
     gzip
 
@@ -53,9 +54,21 @@ EOF
 # Configure cloud-init to support all standard cloud datasources (OpenStack, Ec2, NoCloud, ConfigDrive)
 cat << 'EOF' > /etc/cloud/cloud.cfg.d/99-cloud-init.cfg
 datasource_list: [ NoCloud, ConfigDrive, OpenStack, Ec2, None ]
+disable_vm_template: false
 EOF
 
-# Ensure DHCP on eth0
+# Ensure automatic DHCP via systemd-networkd and ifupdown
+mkdir -p /etc/systemd/network
+cat << 'EOF' > /etc/systemd/network/10-eth.network
+[Match]
+Name=eth* en*
+
+[Network]
+DHCP=yes
+EOF
+systemctl enable systemd-networkd systemd-resolved || true
+
+# Ensure DHCP on eth0 for legacy ifupdown
 mkdir -p /etc/network/interfaces.d
 cat << 'EOF' > /etc/network/interfaces.d/eth0
 auto eth0