fix: sync dev branch with main timeline/schema changes and remove stale providers

Forward-port main's timeline epoch tracking, projected window selection,
and schema updates into dev. Remove aider/amp/gemini providers and
provider-history-compatibility layers that are no longer needed.

packages/app/package.json

@@ -81,8 +81,8 @@
     "expo-web-browser": "~15.0.8",
     "lucide-react-native": "^0.546.0",
     "mnemonic-id": "^3.2.7",
-    "react": "19.1.4",
-    "react-dom": "19.1.4",
+    "react": "19.1.0",
+    "react-dom": "19.1.0",
     "react-native": "^0.81.5",
     "react-native-css": "^3.0.1",
     "react-native-draggable-flatlist": "^4.0.3",