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.

package-lock.json

@@ -32,8 +32,8 @@
         "get-port-cli": "^3.0.0",
         "knip": "^5.82.1",
         "patch-package": "^8.0.1",
-        "react": "19.1.4",
-        "react-dom": "19.1.4",
+        "react": "19.1.0",
+        "react-dom": "19.1.0",
         "typescript": "^5.9.3"
       }
     },
@@ -29122,9 +29122,9 @@
       }
     },
     "node_modules/react": {
-      "version": "19.1.4",
-      "resolved": "https://registry.npmjs.org/react/-/react-19.1.4.tgz",
-      "integrity": "sha512-DHINL3PAmPUiK1uszfbKiXqfE03eszdt5BpVSuEAHb5nfmNPwnsy7g39h2t8aXFc/Bv99GH81s+j8dobtD+jOw==",
+      "version": "19.1.0",
+      "resolved": "https://registry.npmjs.org/react/-/react-19.1.0.tgz",
+      "integrity": "sha512-FS+XFBNvn3GTAWq26joslQgWNoFu08F4kl0J4CgdNKADkdSGXQyTCnKteIAJy96Br6YbpEU1LSzV5dYtjMkMDg==",
       "license": "MIT",
       "engines": {
         "node": ">=0.10.0"
@@ -29162,15 +29162,15 @@
       }
     },
     "node_modules/react-dom": {
-      "version": "19.1.4",
-      "resolved": "https://registry.npmjs.org/react-dom/-/react-dom-19.1.4.tgz",
-      "integrity": "sha512-s2868ab/xo2SI6H4106A7aFI8Mrqa4xC6HZT/pBzYyQ3cBLqa88hu47xYD8xf+uECleN698Awn7RCWlkTiKnqQ==",
+      "version": "19.1.0",
+      "resolved": "https://registry.npmjs.org/react-dom/-/react-dom-19.1.0.tgz",
+      "integrity": "sha512-Xs1hdnE+DyKgeHJeJznQmYMIBG3TKIHJJT95Q58nHLSrElKlGQqDTR2HQ9fx5CN/Gk6Vh/kupBTDLU11/nDk/g==",
       "license": "MIT",
       "dependencies": {
         "scheduler": "^0.26.0"
       },
       "peerDependencies": {
-        "react": "^19.1.4"
+        "react": "^19.1.0"
       }
     },
     "node_modules/react-error-boundary": {
@@ -34911,8 +34911,8 @@
         "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",