Add .gitignore and package-lock.json files

- Add comprehensive .gitignore for binaries, node_modules, and build outputs
- Add package-lock.json for cmd/acb-indexer and worker-api
- Ensures reproducible builds with exact dependency versions

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

.gitignore

@@ -0,0 +1,32 @@
+# Binaries
+acb-local
+acb-mapgen
+acb-worker
+
+# Node modules
+node_modules/
+
+# Build outputs
+dist/
+*.js.map
+
+# Environment files
+.env
+.env.local
+.env.*.local
+
+# IDE
+.idea/
+.vscode/
+*.swp
+*.swo
+
+# OS files
+.DS_Store
+Thumbs.db
+
+# Test outputs
+replay.json
+
+# Marathon instructions (local only)
+.marathon/