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-k8s-ready.sh

@@ -0,0 +1,69 @@
+#!/bin/bash
+# test-k8s-ready.sh — Verify K8s node reaches Ready state
+# Usage: ./test/integration/test-k8s-ready.sh <iso-path>
+# Requires: kubectl on host, QEMU with port forwarding
+set -euo pipefail
+
+ISO="${1:?Usage: $0 <path-to-iso>}"
+TIMEOUT_BOOT=120
+TIMEOUT_K8S=300
+API_PORT=6443
+
+DATA_DISK=$(mktemp /tmp/kubesolo-data-XXXXXX.img)
+dd if=/dev/zero of="$DATA_DISK" bs=1M count=1024 2>/dev/null
+mkfs.ext4 -q -L KSOLODATA "$DATA_DISK" 2>/dev/null
+
+cleanup() {
+    kill "$QEMU_PID" 2>/dev/null || true
+    rm -f "$DATA_DISK"
+}
+trap cleanup EXIT
+
+echo "==> K8s readiness test: $ISO"
+
+# Launch QEMU with API port forwarded
+qemu-system-x86_64 \
+    -m 2048 -smp 2 \
+    -nographic \
+    -cdrom "$ISO" \
+    -boot d \
+    -drive "file=$DATA_DISK,format=raw,if=virtio" \
+    -net nic,model=virtio \
+    -net user,hostfwd=tcp::${API_PORT}-:6443 \
+    -append "console=ttyS0,115200n8 kubesolo.data=/dev/vda" \
+    &
+QEMU_PID=$!
+
+# Wait for API server
+echo "    Waiting for K8s API on localhost:${API_PORT}..."
+ELAPSED=0
+while [ "$ELAPSED" -lt "$TIMEOUT_K8S" ]; do
+    if kubectl --kubeconfig=/dev/null \
+        --server="https://localhost:${API_PORT}" \
+        --insecure-skip-tls-verify \
+        get nodes 2>/dev/null | grep -q "Ready"; then
+        echo ""
+        echo "==> PASS: K8s node is Ready (${ELAPSED}s)"
+
+        # Bonus: try deploying a pod
+        echo "    Deploying test pod..."
+        kubectl --server="https://localhost:${API_PORT}" --insecure-skip-tls-verify \
+            run test-nginx --image=nginx:alpine --restart=Never 2>/dev/null || true
+
+        sleep 10
+        if kubectl --server="https://localhost:${API_PORT}" --insecure-skip-tls-verify \
+            get pod test-nginx 2>/dev/null | grep -q "Running"; then
+            echo "==> PASS: Test pod is Running"
+        else
+            echo "==> WARN: Test pod not Running (may need more time or image pull)"
+        fi
+        exit 0
+    fi
+    sleep 5
+    ELAPSED=$((ELAPSED + 5))
+    printf "\r    Elapsed: %ds / %ds" "$ELAPSED" "$TIMEOUT_K8S"
+done
+
+echo ""
+echo "==> FAIL: K8s node did not reach Ready within ${TIMEOUT_K8S}s"
+exit 1