migration: establish exact preserved app baseline

docs/migration/保真迁移状态.json

@@ -1,17 +1,18 @@
 {
   "schema_version": 1,
-  "updated_at": "2026-07-30T22:51:21+08:00",
-  "status": "preparation",
+  "updated_at": "2026-07-30T23:55:00+08:00",
+  "status": "active",
   "migration_mode": "behavior_preserving_source_migration",
   "source_of_truth": "current_original_webapp_runtime_and_source",
   "source_root": ".",
-  "target_root": null,
+  "target_root": "app",
   "failed_roots": [
     "next"
   ],
   "current_slice": null,
+  "last_completed_slice": "slice-00-exact-runtime-copy",
   "last_checkpoint": "xiaobai-preservation-migration-charter-20260730",
-  "next_action": "inventory_original_assets_and_propose_target_structure_before_copying_code",
+  "next_action": "commit_and_push_slice-00_then_begin_startup_http_account_migration",
   "authoritative_documents": [
     "AGENTS.md",
     "docs/migration/原版保真迁移总纲.md",
@@ -27,9 +28,11 @@
     "keep_original_runtime_available",
     "do_not_delete_uncertain_code"
   ],
-  "open_decisions": [
-    "target_directory_name",
-    "target_directory_structure",
-    "migration_slice_order"
-  ]
+  "approved_decisions": {
+    "target_directory_name": "app",
+    "target_directory_structure": "approved_2026-07-30",
+    "migration_slice_order": "approved_2026-07-30",
+    "execution_mode": "autonomous_until_complete"
+  },
+  "open_decisions": []
 }