Update shift assignment date filtering to improve accuracy

Modify the query in `server/routes.ts` to correctly filter shift assignments by comparing the date part of `shifts.startTime` with `routeData.shiftDate`.

Replit-Commit-Author: Agent
Replit-Commit-Session-Id: e5565357-90e1-419f-b9a8-6ee8394636df
Replit-Commit-Checkpoint-Type: full_checkpoint
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server/routes.ts

@@ -3708,7 +3708,7 @@ export async function registerRoutes(app: Express): Promise<Server> {
         .where(
           and(
             eq(shiftAssignments.guardId, routeData.guardId),
-            eq(shifts.shiftDate, routeData.shiftDate)
+            sql`DATE(${shifts.startTime}) = ${routeData.shiftDate}`
           )
         )
         .limit(1);