feat: install logging, error trapping, PXE/ISO integration tests

Kickstart installs on real hardware failed silently — no error reporting,
only 3 progress callbacks, zero log streaming. This overhaul makes every
install fully observable.

Kickstart improvements:
- Error trapping in %pre and %post (trap ERR sends failure details to bastion)
- 12+ granular progress stages (was 3): SSH, hostname, k3s prep, EFI boot, metadata
- Background log streamer: tails %post output and batch-sends to /api/log
- bastion_log() function for explicit log lines from kickstart scripts

Bastion API:
- POST /api/log — receives raw log lines from kickstart (single or batch)
- InstallLogBuffer — per-MAC ring buffer (2000 lines) + file persistence
- GET /api/logs/:mac — now returns log_lines + log_total alongside stages
- SSE /api/logs/:mac/follow — uses named events (event: stage vs event: log)
- Progress events forwarded to labd via bastion-progress WebSocket message
- Post-provision k3s logs routed through progressBus (was console-only)

dnsmasq fixes found during VM testing:
- HTTP Boot filename: ipxe-real.efi → ipxe.efi (leftover from old 2-stage approach)
- pxe-service directives: only in proxy mode (breaks OVMF PXE in full mode)
- PXEClient vendor class echo for UEFI firmware compatibility

Integration tests:
- PXE boot test: blank UEFI VM → dnsmasq → HTTP Boot → iPXE → bastion → install
- ISO boot test: blank VM boots from bastion-generated ISO → same flow
- Shared helpers: pxe-network (no DHCP, nftables fix), pxe-vm (UEFI + ISO boot)
- test-provision.sh: runs both PXE + ISO tests with prerequisite checks
- 250GB sparse QCOW2 disk (LVM layout needs ~204GB)

201 unit tests passing (11 new).

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

bastion/deploy/k8s/labd/base/deployment.yaml

@@ -0,0 +1,44 @@
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: labd
+spec:
+  replicas: 1
+  selector:
+    matchLabels:
+      app: labd
+  template:
+    metadata:
+      labels:
+        app: labd
+    spec:
+      containers:
+        - name: labd
+          image: mysources.co.uk/michal/lab/labd:latest
+          imagePullPolicy: Always
+          ports:
+            - containerPort: 3100
+          envFrom:
+            - configMapRef:
+                name: labd-config
+            - secretRef:
+                name: labd-secrets
+          livenessProbe:
+            httpGet:
+              path: /health/live
+              port: 3100
+            initialDelaySeconds: 10
+            periodSeconds: 15
+          readinessProbe:
+            httpGet:
+              path: /health/ready
+              port: 3100
+            initialDelaySeconds: 5
+            periodSeconds: 10
+          resources:
+            requests:
+              cpu: 100m
+              memory: 128Mi
+            limits:
+              cpu: 500m
+              memory: 512Mi