Add Maestro-style YAML flow runner for deterministic automation

New --flow mode executes scripted YAML steps without LLM, mapping 17
commands (tap, type, swipe, scroll, etc.) to existing actions. Element
finding uses accessibility tree text/hint/id matching.

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

package.json

@@ -14,6 +14,7 @@
     "ai": "^6.0.72",
     "fast-xml-parser": "^4.5.0",
     "openai": "^4.73.0",
+    "yaml": "^2.8.2",
     "zod": "^4.3.6"
   },
   "devDependencies": {