feat(sync): complete incremental sync protocol with storage-pull, state management, and tests (#799)

- Add storage-pull strategy: rclone-based sync from remote storage with
  overlay and clean modes, URI parsing (storage://remote:bucket/path),
  transfer parallelism, and automatic rclone availability checking
- Add SyncStateManager: persistent state load/save with configurable
  paths, workspace hash calculation via SHA-256 of key project files,
  and drift detection for external modification awareness
- Add action.yml inputs: syncStrategy, syncInputRef, syncStorageRemote,
  syncRevertAfter, syncStatePath with sensible defaults
- Wire sync into Input (5 getters), BuildParameters (5 fields), index.ts
  (local build path), and RemoteClient (orchestrator path) with post-job
  overlay revert when syncRevertAfter is true
- Add 42 unit tests covering all strategies, URI parsing, state
  management, hash calculation, drift detection, error handling, and
  edge cases (missing rclone, invalid URIs, absent state, empty diffs)
- Add root:true to eslintrc to prevent plugin resolution conflicts

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

action.yml

@@ -182,8 +182,8 @@ inputs:
     required: false
     default: ''
     description:
-      '[Orchestrator] Run a custom job instead of the standard build automation for orchestrator (in yaml format with the
-      keys image, secrets (name, value object array), command line string)'
+      '[Orchestrator] Run a custom job instead of the standard build automation for orchestrator (in yaml format with
+      the keys image, secrets (name, value object array), command line string)'
   awsStackName:
     default: 'game-ci'
     required: false
@@ -279,6 +279,24 @@ inputs:
     description:
       '[Orchestrator] Specifies the repo for the unity builder. Useful if you forked the repo for testing, features, or
       fixes.'
+  syncStrategy:
+    description: 'Workspace sync strategy: full, git-delta, direct-input, storage-pull'
+    required: false
+    default: 'full'
+  syncInputRef:
+    description: 'URI for direct-input or storage-pull content (storage://remote/path or file path)'
+    required: false
+  syncStorageRemote:
+    description: 'rclone remote name for storage-backed inputs (defaults to rcloneRemote)'
+    required: false
+  syncRevertAfter:
+    description: 'Revert overlaid changes after job completion'
+    required: false
+    default: 'true'
+  syncStatePath:
+    description: 'Path to sync state file for delta tracking'
+    required: false
+    default: '.game-ci/sync-state.json'
 
 outputs:
   volume: