fix: add explicit type annotations to setState callbacks in time-range-context

Fixes TypeScript strict mode error where callback parameters implicitly had 'any' type.

lib/time-range-context.tsx

@@ -68,24 +68,24 @@ export function TimeRangeProvider({ children }: { children: ReactNode }) {
 
   const setRange = useCallback((r: TimeRange) => {
     setRangeState(r);
-    setCustomStartState(prev => {
+    setCustomStartState((prev: string) => {
-      setCustomEndState(end => { persist(r, prev, end); return end; });
+      setCustomEndState((end: string) => { persist(r, prev, end); return end; });
       return prev;
     });
   }, []);
 
   const setCustomStart = useCallback((s: string) => {
     setCustomStartState(s);
-    setRangeState(r => {
+    setRangeState((r: TimeRange) => {
-      setCustomEndState(end => { persist(r, s, end); return end; });
+      setCustomEndState((end: string) => { persist(r, s, end); return end; });
       return r;
     });
   }, []);
 
   const setCustomEnd = useCallback((e: string) => {
     setCustomEndState(e);
-    setRangeState(r => {
+    setRangeState((r: TimeRange) => {
-      setCustomStartState(start => { persist(r, start, e); return start; });
+      setCustomStartState((start: string) => { persist(r, start, e); return start; });
       return r;
     });
   }, []);