build(deps): upgrade to React 19 (coordinated with react-leaflet 5)

client/package.json

@@ -13,10 +13,10 @@
     "leaflet": "^1.9.4",
     "lucide-react": "^1.14.0",
     "portos-ai-toolkit": "^0.8.4",
-    "react": "^18.3.1",
-    "react-dom": "^18.3.1",
+    "react": "^19.2.5",
+    "react-dom": "^19.2.7",
     "react-hot-toast": "^2.6.0",
-    "react-leaflet": "^4.2.1",
+    "react-leaflet": "^5.0.0",
     "react-router-dom": "^7.16.0",
     "socket.io-client": "^4.8.3",
     "zustand": "^5.0.12"
@@ -26,8 +26,8 @@
     "@testing-library/react": "^16.3.2",
     "@types/d3": "^7.4.3",
     "@types/leaflet": "^1.9.21",
-    "@types/react": "^18.3.28",
-    "@types/react-dom": "^18.3.7",
+    "@types/react": "^19.2.14",
+    "@types/react-dom": "^19.2.3",
     "@vitejs/plugin-react": "^6.0.2",
     "tailwindcss": "^4.3.1",
     "typescript": "^6.0.2",

client/src/components/ai/AiDiscoveryModal.tsx

@@ -372,7 +372,7 @@ export function AiDiscoveryModal({ dbId, onClose, onComplete }: AiDiscoveryModal
                             <div className="flex items-center gap-2 flex-wrap">
                               <Link
                                 to={`/person/${dbId}/${candidate.personId}`}
-                                onClick={e => e.stopPropagation()}
+                                onClick={(e: React.MouseEvent) => e.stopPropagation()}
                                 className="font-medium text-app-text hover:text-app-accent transition-colors"
                               >
                                 {candidate.name}

client/src/components/ancestry-tree/FamilyUnitCard.tsx

@@ -1,6 +1,7 @@
 import type { AncestryFamilyUnit } from '@fsf/shared';
 import { PersonCard } from './PersonCard';
 import { useRef, useEffect, useState } from 'react';
+import type { JSX } from 'react';
 
 interface FamilyUnitCardProps {
   unit: AncestryFamilyUnit;

client/src/components/person/LinkRelationshipDialog.tsx

@@ -37,7 +37,7 @@ export function LinkRelationshipDialog({ open, dbId, personId, defaultType, onCl
 
   const [saving, setSaving] = useState(false);
   const inputRef = useRef<HTMLInputElement>(null);
-  const searchTimerRef = useRef<ReturnType<typeof setTimeout>>();
+  const searchTimerRef = useRef<ReturnType<typeof setTimeout>>(undefined);
 
   useEffect(() => {
     if (open) {

client/src/components/person/RelationshipModal.tsx

@@ -38,7 +38,7 @@ export function RelationshipModal({ open, dbId, personId, initialType, onClose,
   const [newName, setNewName] = useState('');
   const [newGender, setNewGender] = useState<'male' | 'female' | 'unknown'>('unknown');
   const inputRef = useRef<HTMLInputElement>(null);
-  const debounceRef = useRef<ReturnType<typeof setTimeout>>();
+  const debounceRef = useRef<ReturnType<typeof setTimeout>>(undefined);
   // Monotonically increasing request id so out-of-order responses from
   // earlier searches don't overwrite results from a newer search.
   const searchRequestIdRef = useRef(0);

client/src/components/ui/CopyButton.tsx

@@ -11,7 +11,7 @@ interface CopyButtonProps {
 
 export function CopyButton({ text, label = 'Copied!', size = 14, className = '' }: CopyButtonProps) {
   const [copied, setCopied] = useState(false);
-  const timeoutRef = useRef<ReturnType<typeof setTimeout>>();
+  const timeoutRef = useRef<ReturnType<typeof setTimeout>>(undefined);
 
   useEffect(() => {
     return () => clearTimeout(timeoutRef.current);