docs(01): add validation strategy for phase 1

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

.planning/config.json

@@ -25,7 +25,8 @@
     "text_mode": false,
     "research_before_questions": false,
     "discuss_mode": "discuss",
-    "skip_discuss": false
+    "skip_discuss": false,
+    "_auto_chain_active": false
   },
   "hooks": {
     "context_warnings": true