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>

dist/index.js

@@ -375,6 +375,12 @@ class BuildParameters {
             cacheUnityInstallationOnMac: input_1.default.cacheUnityInstallationOnMac,
             unityHubVersionOnMac: input_1.default.unityHubVersionOnMac,
             dockerWorkspacePath: input_1.default.dockerWorkspacePath,
+            gitIntegrityCheck: input_1.default.gitIntegrityCheck,
+            gitAutoRecover: input_1.default.gitAutoRecover,
+            cleanReservedFilenames: input_1.default.cleanReservedFilenames,
+            buildArchiveEnabled: input_1.default.buildArchiveEnabled,
+            buildArchivePath: input_1.default.buildArchivePath,
+            buildArchiveRetention: input_1.default.buildArchiveRetention,
         };
     }
     static parseBuildFile(filename, platform, androidExportType) {
@@ -1826,6 +1832,28 @@ class Input {
     static get skipActivation() {
         return Input.getInput('skipActivation')?.toLowerCase() ?? 'false';
     }
+    static get gitIntegrityCheck() {
+        const input = Input.getInput('gitIntegrityCheck') ?? false;
+        return input === 'true';
+    }
+    static get gitAutoRecover() {
+        const input = Input.getInput('gitAutoRecover') ?? 'true';
+        return input === 'true';
+    }
+    static get cleanReservedFilenames() {
+        const input = Input.getInput('cleanReservedFilenames') ?? false;
+        return input === 'true';
+    }
+    static get buildArchiveEnabled() {
+        const input = Input.getInput('buildArchiveEnabled') ?? false;
+        return input === 'true';
+    }
+    static get buildArchivePath() {
+        return Input.getInput('buildArchivePath') ?? '';
+    }
+    static get buildArchiveRetention() {
+        return Number.parseInt(Input.getInput('buildArchiveRetention') ?? '3', 10);
+    }
     static ToEnvVarFormat(input) {
         if (input.toUpperCase() === input) {
             return input;