grandfather in functionality for db.date bc its only used in one spot

Author: chpy04

src/backend/src/utils/change-requests.utils.ts

@@ -21,8 +21,7 @@ import {
   WorkPackageProposedChangesCreateArgs,
   WorkPackageStage,
   User,
-  formatDateOnly,
-  toDateString
+  formatDateOnly
 } from 'shared';
 import { DeletedException, HttpException, NotFoundException } from './errors.utils.js';
 import { ChangeRequestStatus } from 'shared';
@@ -449,7 +448,7 @@ export const applyWorkPackageProposedChanges = async (
       workPackageProposedChanges.wbsProposedChanges.name,
       crId,
       workPackageProposedChanges.stage as WorkPackageStage,
-      toDateString(workPackageProposedChanges.startDate),
+      workPackageProposedChanges.startDate.toISOString().split('T')[0],
       workPackageProposedChanges.duration,
       workPackageProposedChanges.blockedBy,
       workPackageProposedChanges.wbsProposedChanges.proposedDescriptionBulletChanges.map(
@@ -465,7 +464,7 @@ export const applyWorkPackageProposedChanges = async (
       wbsProposedChanges.name,
       crId,
       workPackageProposedChanges.stage as WorkPackageStage,
-      toDateString(workPackageProposedChanges.startDate),
+      workPackageProposedChanges.startDate.toISOString().split('T')[0],
       workPackageProposedChanges.duration,
       workPackageProposedChanges.blockedBy,
       wbsProposedChanges.proposedDescriptionBulletChanges.map(descriptionBulletToDescriptionBulletPreview),

src/frontend/src/apis/work-packages.api.ts

@@ -4,7 +4,14 @@
  */
 
 import axios from '../utils/axios';
-import { dateToMidnightUTC, DescriptionBulletPreview, WbsNumber, WorkPackage, WorkPackagePreview, WorkPackageStage } from 'shared';
+import {
+  dateToMidnightUTC,
+  DescriptionBulletPreview,
+  WbsNumber,
+  WorkPackage,
+  WorkPackagePreview,
+  WorkPackageStage
+} from 'shared';
 import { wbsPipe } from '../utils/pipes';
 import { apiUrls } from '../utils/urls';
 import { workPackagePreviewTransformer, workPackageTransformer } from './transformers/work-packages.transformers';

src/frontend/src/pages/CalendarPage/CalendarWeekView.tsx

@@ -224,15 +224,12 @@ const CalendarWeekView: React.FC<CalendarWeekViewProps> = ({
   );
 
   // Build per-day task lists (tasks appear on their deadline day)
-  // Task deadlines are date-only values (@db.Date, midnight UTC).
-  // Extract UTC components from deadline, local components from weekDay, and compare.
+  // Task deadlines are date-only values normalized to local midnight by dbDateToLocalDate
+  // in the transformer, so compare local components on both sides.
   const tasksByDay: CalendarTask[][] = weekDays.map((day) =>
     tasks.filter((t) => {
       if (!t.deadline) return false;
-      const d = new Date(t.deadline);
-      return (
-        d.getUTCFullYear() === day.getFullYear() && d.getUTCMonth() === day.getMonth() && d.getUTCDate() === day.getDate()
-      );
+      return isSameDay(new Date(t.deadline), day);
     })
   );
 

src/frontend/src/pages/GanttPage/GanttChart/GanttChartComponents/GanttTaskBar/GanttTaskBar.tsx

@@ -45,15 +45,15 @@ const GanttTaskBar = <T,>({
   highlightTaskComparator
 }: GanttTaskBarProps<T>) => {
   const getStartCol = (start: Date) => {
-    const startCol = days.findIndex((day) => toDateString(day) === toDateString(getMonday(start, true))) + 1;
+    const startCol = days.findIndex((day) => toDateString(day) === toDateString(getMonday(start))) + 1;
     return startCol;
   };
 
   const getEndCol = (end: Date) => {
     const endCol =
-      days.findIndex((day) => toDateString(day) === toDateString(getMonday(end, true))) === -1
+      days.findIndex((day) => toDateString(day) === toDateString(getMonday(end))) === -1
         ? days.length + 1
-        : days.findIndex((day) => toDateString(day) === toDateString(getMonday(end, true))) + 2;
+        : days.findIndex((day) => toDateString(day) === toDateString(getMonday(end))) + 2;
     return endCol;
   };