feat: debug --sshd flag, auto SSH + nc listener + IP callback

When using `labctl provision debug <target> --sshd`, the rescue
kickstart generates host keys, starts sshd (pw: debug) and nc
listener (port 2323), and reports the IP back to bastion via
/api/progress callback. Fully self-contained, no mounted FS needed.

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

bastion/src/shared/src/protocol/index.ts

@@ -111,7 +111,7 @@ export type LabdBastionMessage =
   | { type: "command-install"; requestId: string; mac: string; hostname: string; disk?: string; role: string; os: string }
   | { type: "command-forget"; requestId: string; mac: string }
   | { type: "command-role-update"; requestId: string; mac: string; role: string }
-  | { type: "command-debug"; requestId: string; mac: string }
+  | { type: "command-debug"; requestId: string; mac: string; sshd?: boolean }
   | { type: "server-shutdown"; reconnectAfter: number };
 
 export type BastionMessageType = BastionMessage["type"];

bastion/src/shared/src/types/state.ts

@@ -101,6 +101,7 @@ export interface InstalledInfo {
 export interface DebugConfig {
   hostname: string;
   queued_at: string;
+  sshd?: boolean;
 }
 
 export interface BastionState {