Share install and deploy preparation with verified release bundle reuse

script/lib/prepare-galaxy-build.d.mts

@@ -0,0 +1,23 @@
+export interface BuildStepUpdate {
+  status?: 'pending' | 'running' | 'done' | 'error';
+  detail?: string;
+}
+
+export interface BuildObserver {
+  updateStep(index: number, update: BuildStepUpdate): void;
+  appendLog(index: number, line: string): void;
+}
+
+export interface PreparedGalaxyBuild {
+  /** Private Galaxy.app copy; safe for consumers to sign without changing the cache. */
+  appPath: string;
+  reused: boolean;
+  identity?: Record<string, unknown>;
+  /** Call in a finally block after the app has been copied or packaged. */
+  release(): Promise<void>;
+}
+
+export function prepareGalaxyBuild(
+  workspaceRoot: string,
+  observer?: BuildObserver | ((index: number, update: BuildStepUpdate) => void),
+): Promise<PreparedGalaxyBuild>;