fix: revert kickstart to near-original baseline (Step 0 — boots clean)

Reverted install.ks.ts to near-original state from commit 64533b2.
This is the bisection baseline — 21/22 integration tests pass,
0 failed systemd services, SSH works, /boot/efi mounts.

Removed all accumulated fixes that collectively broke boot:
- ERR trap, background log streamer, bastion_log/bastion_error
- depmod rebuild, nofail on /boot/efi, SELinux autorelabel
- chcon/restorecon for /etc /var /root
- kernel-modules and dosfstools packages

Kept from current branch:
- rootpw --plaintext lab-root-pw (console debug access)
- Network-first boot order (bastion controls boot)
- Vanilla role support, rancher partition support
- Boot screenshots during SSH wait (1/sec rolling buffer)
- Test runner script (run-pxe-test.sh)

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

bastion/tests/integration/run-pxe-test.sh

@@ -0,0 +1,27 @@
+#!/bin/bash
+# One-shot PXE integration test runner.
+# Compiles, runs unit tests, cleans up, and runs the full integration test.
+set -e
+
+cd "$(dirname "$0")/../.."
+
+echo "=== Step 1: Compile ==="
+npx tsc --noEmit
+echo "✓ Compile OK"
+
+echo ""
+echo "=== Step 2: Kickstart unit tests ==="
+npx vitest run src/bastion/tests/kickstart.test.ts 2>&1 | tail -5
+echo "✓ Unit tests OK"
+
+echo ""
+echo "=== Step 3: Clean up ==="
+sudo lsof -ti:8099 2>/dev/null | xargs -r sudo kill -9 || true
+sudo virsh destroy lab-pxe-test 2>/dev/null || true
+sudo virsh undefine lab-pxe-test --nvram 2>/dev/null || true
+sudo rm -f /var/lib/libvirt/images/lab-pxe-test.qcow2
+echo "✓ Cleanup done"
+
+echo ""
+echo "=== Step 4: Integration test ==="
+npx vitest run -c /dev/null tests/integration/pxe-provision.test.ts 2>&1