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/src/shared/src/index.ts

@@ -1,4 +1,7 @@
 export type {
+  OsId,
+  Arch,
+  Role,
   HardwareInfo,
   InstallConfig,
   InstalledInfo,
@@ -6,4 +9,37 @@ export type {
   BastionConfig,
 } from "./types/index.js";
 
+export { SUPPORTED_OS, SUPPORTED_ROLES, ROLE_REGISTRY, isValidOsId } from "./types/index.js";
+export type { RoleInfo } from "./types/index.js";
+
 export { APP_NAME, APP_VERSION } from "./constants/index.js";
+
+export {
+  type AgentMessage,
+  type ServerMessage,
+  type BastionMessage,
+  type LabdBastionMessage,
+  type JournalOptions,
+  type AgentMessageType,
+  type ServerMessageType,
+  type BastionMessageType,
+  type LabdBastionMessageType,
+  isAgentMessage,
+  isServerMessage,
+  isBastionMessage,
+  isLabdBastionMessage,
+  parseAgentMessage,
+  parseServerMessage,
+  parseBastionMessage,
+  parseLabdBastionMessage,
+  generateRequestId,
+} from "./protocol/index.js";
+
+export {
+  LabError,
+  NotFoundError,
+  PermissionDeniedError,
+  ValidationError,
+  AgentNotConnectedError,
+  isLabError,
+} from "./errors/index.js";