feat(orchestrator): build reliability features — git integrity, reserved filename cleanup, archival

Add three optional reliability features for hardening CI pipelines:
- Git corruption detection & recovery (fsck, stale lock cleanup,
  submodule backing store validation, auto-recovery)
- Reserved filename cleanup (removes Windows device names that
  cause Unity asset importer infinite loops)
- Build output archival with configurable retention policy

All features are opt-in and fail gracefully with warnings only.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/model/build-parameters.ts

@@ -106,6 +106,12 @@ class BuildParameters {
   public cacheUnityInstallationOnMac!: boolean;
   public unityHubVersionOnMac!: string;
   public dockerWorkspacePath!: string;
+  public gitIntegrityCheck!: boolean;
+  public gitAutoRecover!: boolean;
+  public cleanReservedFilenames!: boolean;
+  public buildArchiveEnabled!: boolean;
+  public buildArchivePath!: string;
+  public buildArchiveRetention!: number;
 
   public static shouldUseRetainedWorkspaceMode(buildParameters: BuildParameters) {
     return buildParameters.maxRetainedWorkspaces > 0 && Orchestrator.lockedWorkspace !== ``;
@@ -242,6 +248,12 @@ class BuildParameters {
       cacheUnityInstallationOnMac: Input.cacheUnityInstallationOnMac,
       unityHubVersionOnMac: Input.unityHubVersionOnMac,
       dockerWorkspacePath: Input.dockerWorkspacePath,
+      gitIntegrityCheck: Input.gitIntegrityCheck,
+      gitAutoRecover: Input.gitAutoRecover,
+      cleanReservedFilenames: Input.cleanReservedFilenames,
+      buildArchiveEnabled: Input.buildArchiveEnabled,
+      buildArchivePath: Input.buildArchivePath,
+      buildArchiveRetention: Input.buildArchiveRetention,
     };
   }