feat(orchestrator): enterprise feature support — CLI provider, submodule profiles, caching, LFS, hooks

Add generic enterprise-grade features to the orchestrator, enabling Unity projects with
complex CI/CD pipelines to adopt game-ci/unity-builder with built-in support for:

- CLI provider protocol: JSON-over-stdin/stdout bridge enabling providers in any language
  (Go, Python, Rust, shell) via the `providerExecutable` input
- Submodule profiles: YAML-based selective submodule initialization with glob patterns
  and variant overlays (`submoduleProfilePath`, `submoduleVariantPath`)
- Local build caching: Filesystem-based Library and LFS caching for local builds without
  external cache actions (`localCacheEnabled`, `localCacheRoot`)
- Custom LFS transfer agents: Register external transfer agents like elastic-git-storage
  (`lfsTransferAgent`, `lfsTransferAgentArgs`, `lfsStoragePaths`)
- Git hooks support: Detect and install lefthook/husky with configurable skip lists
  (`gitHooksEnabled`, `gitHooksSkipList`)

Also removes all `orchestrator-develop` branch references, replacing with `main`.

13 new action inputs, 13 new files, 14 new CLI provider tests, 17 submodule tests,
plus cache/LFS/hooks unit tests. All 452 tests pass.

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

src/model/orchestrator/orchestrator.ts

@@ -129,6 +129,17 @@ class Orchestrator {
     // Store whether we should validate AWS templates (used by aws-local mode)
     Orchestrator.validateAwsTemplates = validateAwsTemplates;
 
+    // Check for CLI provider executable
+    if (Orchestrator.buildParameters.providerExecutable) {
+      const { default: CliProvider } = await import('./providers/cli');
+      Orchestrator.Provider = new CliProvider(
+        Orchestrator.buildParameters.providerExecutable,
+        Orchestrator.buildParameters,
+      );
+      OrchestratorLogger.log(`Using CLI provider executable: ${Orchestrator.buildParameters.providerExecutable}`);
+      return;
+    }
+
     switch (provider) {
       case 'k8s':
         Orchestrator.Provider = new Kubernetes(Orchestrator.buildParameters);