feat: initial Phase 1 PoC scaffolding for KubeSolo OS

Complete Phase 1 implementation of KubeSolo OS — an immutable, bootable
Linux distribution built on Tiny Core Linux for running KubeSolo
single-node Kubernetes.

Build system:
- Makefile with fetch, rootfs, initramfs, iso, disk-image targets
- Dockerfile.builder for reproducible builds
- Scripts to download Tiny Core, extract rootfs, inject KubeSolo,
  pack initramfs, and create bootable ISO/disk images

Init system (10 POSIX sh stages):
- Early mount (proc/sys/dev/cgroup2), cmdline parsing, persistent
  mount with bind-mounts, kernel module loading, sysctl, DHCP
  networking, hostname, clock sync, containerd prep, KubeSolo exec

Shared libraries:
- functions.sh (device wait, IP lookup, config helpers)
- network.sh (static IP, config persistence, interface detection)
- health.sh (containerd, API server, node readiness checks)
- Emergency shell for boot failure debugging

Testing:
- QEMU boot test with serial log marker detection
- K8s readiness test with kubectl verification
- Persistence test (reboot + verify state survives)
- Workload deployment test (nginx pod)
- Local storage test (PVC + local-path provisioner)
- Network policy test
- Reusable run-vm.sh launcher

Developer tools:
- dev-vm.sh (interactive QEMU with port forwarding)
- rebuild-initramfs.sh (fast iteration)
- inject-ssh.sh (dropbear SSH for debugging)
- extract-kernel-config.sh + kernel-audit.sh

Documentation:
- Full design document with architecture research
- Boot flow documentation covering all 10 init stages
- Cloud-init examples (DHCP, static IP, Portainer Edge, air-gapped)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

test/integration/test-local-storage.sh

@@ -0,0 +1,126 @@
+#!/bin/bash
+# test-local-storage.sh — Verify PVC with local-path provisioner works
+# Usage: ./test/integration/test-local-storage.sh <iso-path>
+# Requires: kubectl on host, QEMU
+set -euo pipefail
+
+ISO="${1:?Usage: $0 <path-to-iso>}"
+TIMEOUT_K8S=300
+TIMEOUT_PVC=120
+API_PORT=6443
+
+DATA_DISK=$(mktemp /tmp/kubesolo-data-XXXXXX.img)
+dd if=/dev/zero of="$DATA_DISK" bs=1M count=2048 2>/dev/null
+mkfs.ext4 -q -L KSOLODATA "$DATA_DISK" 2>/dev/null
+
+SERIAL_LOG=$(mktemp /tmp/kubesolo-storage-XXXXXX.log)
+
+cleanup() {
+    # Clean up K8s resources
+    $KUBECTL delete pod test-storage --grace-period=0 --force 2>/dev/null || true
+    $KUBECTL delete pvc test-pvc 2>/dev/null || true
+    kill "$QEMU_PID" 2>/dev/null || true
+    rm -f "$DATA_DISK" "$SERIAL_LOG"
+}
+trap cleanup EXIT
+
+KUBECTL="kubectl --server=https://localhost:${API_PORT} --insecure-skip-tls-verify"
+
+echo "==> Local storage test: $ISO"
+
+# Launch QEMU
+qemu-system-x86_64 \
+    -m 2048 -smp 2 \
+    -nographic \
+    -cdrom "$ISO" \
+    -boot d \
+    -drive "file=$DATA_DISK,format=raw,if=virtio" \
+    -net nic,model=virtio \
+    -net "user,hostfwd=tcp::${API_PORT}-:6443" \
+    -serial "file:$SERIAL_LOG" \
+    -append "console=ttyS0,115200n8 kubesolo.data=/dev/vda" \
+    &
+QEMU_PID=$!
+
+# Wait for K8s API
+echo "    Waiting for K8s API..."
+ELAPSED=0
+while [ "$ELAPSED" -lt "$TIMEOUT_K8S" ]; do
+    if $KUBECTL get nodes 2>/dev/null | grep -q "Ready"; then
+        break
+    fi
+    sleep 5
+    ELAPSED=$((ELAPSED + 5))
+done
+
+if [ "$ELAPSED" -ge "$TIMEOUT_K8S" ]; then
+    echo "==> FAIL: K8s not ready within ${TIMEOUT_K8S}s"
+    exit 1
+fi
+echo "    K8s ready (${ELAPSED}s)"
+
+# Create PVC
+echo "==> Creating PersistentVolumeClaim..."
+$KUBECTL apply -f - << 'YAML'
+apiVersion: v1
+kind: PersistentVolumeClaim
+metadata:
+  name: test-pvc
+spec:
+  accessModes:
+    - ReadWriteOnce
+  resources:
+    requests:
+      storage: 64Mi
+YAML
+
+# Create pod that uses the PVC
+echo "==> Creating pod with PVC..."
+$KUBECTL apply -f - << 'YAML'
+apiVersion: v1
+kind: Pod
+metadata:
+  name: test-storage
+spec:
+  containers:
+    - name: writer
+      image: busybox:latest
+      command: ["sh", "-c", "echo 'kubesolo-storage-test' > /data/test.txt && sleep 3600"]
+      volumeMounts:
+        - name: data
+          mountPath: /data
+  volumes:
+    - name: data
+      persistentVolumeClaim:
+        claimName: test-pvc
+YAML
+
+# Wait for pod Running
+echo "    Waiting for storage pod..."
+ELAPSED=0
+while [ "$ELAPSED" -lt "$TIMEOUT_PVC" ]; do
+    STATUS=$($KUBECTL get pod test-storage -o jsonpath='{.status.phase}' 2>/dev/null || echo "")
+    if [ "$STATUS" = "Running" ]; then
+        break
+    fi
+    sleep 5
+    ELAPSED=$((ELAPSED + 5))
+done
+
+if [ "$STATUS" != "Running" ]; then
+    echo "==> FAIL: Storage pod did not reach Running (status: $STATUS)"
+    $KUBECTL describe pod test-storage 2>/dev/null | tail -20 || true
+    exit 1
+fi
+
+# Verify data was written
+sleep 3
+DATA=$($KUBECTL exec test-storage -- cat /data/test.txt 2>/dev/null || echo "")
+if [ "$DATA" = "kubesolo-storage-test" ]; then
+    echo "==> PASS: Local storage provisioning works"
+    echo "    PVC bound, pod running, data written and read back successfully"
+    exit 0
+else
+    echo "==> FAIL: Data verification failed (got: '$DATA')"
+    exit 1
+fi