Fix QA findings: combine todo queries, remove dead prop, add aria-labels

- Merge total_todos and total_incomplete_todos into single DB query (W-04)
- Remove unused `days` prop from UpcomingWidget interface (W-03)
- Add aria-label to focus/show-past toggle buttons (S-08)
- Add zero-duration event guard in CalendarWidget progress calc (S-07)
- Combine duplicate date-utils imports (S-01)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

backend/app/routers/dashboard.py

@@ -1,6 +1,6 @@
 from fastapi import APIRouter, Depends, Query
 from sqlalchemy.ext.asyncio import AsyncSession
-from sqlalchemy import select, func, or_
+from sqlalchemy import select, func, or_, case
 from datetime import datetime, date, timedelta
 from typing import Optional, List, Dict, Any
 
@@ -84,20 +84,16 @@ async def get_dashboard(
     projects_by_status_result = await db.execute(projects_by_status_query)
     projects_by_status = {row[0]: row[1] for row in projects_by_status_result}
 
-    # Total incomplete todos count (scoped to user)
-    total_incomplete_result = await db.execute(
-        select(func.count(Todo.id)).where(
-            Todo.user_id == current_user.id,
-            Todo.completed == False,
-        )
+    # Todo counts: total and incomplete in a single query
+    todo_counts_result = await db.execute(
+        select(
+            func.count(Todo.id).label("total"),
+            func.count(case((Todo.completed == False, Todo.id))).label("incomplete"),
+        ).where(Todo.user_id == current_user.id)
     )
-    total_incomplete_todos = total_incomplete_result.scalar()
-
-    # Total todos count (for progress ring ratio)
-    total_todos_result = await db.execute(
-        select(func.count(Todo.id)).where(Todo.user_id == current_user.id)
-    )
-    total_todos = total_todos_result.scalar()
+    todo_row = todo_counts_result.one()
+    total_todos = todo_row.total
+    total_incomplete_todos = todo_row.incomplete
 
     # Starred events (upcoming, ordered by date, scoped to user's calendars)
     starred_query = select(CalendarEvent).where(

frontend/src/components/dashboard/CalendarWidget.tsx

@@ -33,6 +33,7 @@ function getProgressPercent(event: DashboardEvent, now: Date): number {
   if (event.all_day) return 0;
   const start = new Date(event.start_datetime).getTime();
   const end = new Date(event.end_datetime).getTime();
+  if (end <= start) return 0;
   const current = now.getTime();
   if (current >= end) return 100;
   if (current <= start) return 0;

frontend/src/components/dashboard/DashboardPage.tsx

@@ -272,7 +272,7 @@ export default function DashboardPage() {
           <div className="grid gap-3 sm:gap-5 lg:grid-cols-5 animate-slide-up" style={{ animationDelay: '100ms', animationFillMode: 'backwards' }}>
             {/* Left: Upcoming feed (wider) */}
             <div className="lg:col-span-3 flex flex-col">
-              <UpcomingWidget items={upcomingData?.items ?? []} days={upcomingData?.days} />
+              <UpcomingWidget items={upcomingData?.items ?? []} />
             </div>
 
             {/* Right: Countdown + Today's events + todos stacked */}

frontend/src/components/dashboard/UpcomingWidget.tsx

@@ -17,13 +17,11 @@ import type { UpcomingItem } from '@/types';
 import { Card, CardContent, CardHeader, CardTitle } from '@/components/ui/card';
 import { ScrollArea } from '@/components/ui/scroll-area';
 import { cn } from '@/lib/utils';
-import { getRelativeTime } from '@/lib/date-utils';
-import { toLocalDatetime } from '@/lib/date-utils';
+import { getRelativeTime, toLocalDatetime } from '@/lib/date-utils';
 import api from '@/lib/api';
 
 interface UpcomingWidgetProps {
   items: UpcomingItem[];
-  days?: number;
 }
 
 const typeConfig: Record<string, { hoverGlow: string; pillBg: string; pillText: string; label: string }> = {
@@ -216,6 +214,7 @@ export default function UpcomingWidget({ items }: UpcomingWidgetProps) {
                 focusMode ? 'bg-accent/15 text-accent' : 'text-muted-foreground hover:text-foreground hover:bg-white/5'
               )}
               title={focusMode ? 'Show all days' : 'Focus: Today + Tomorrow'}
+              aria-label={focusMode ? 'Show all days' : 'Focus: Today + Tomorrow'}
             >
               <Target className="h-3.5 w-3.5" />
             </button>
@@ -226,6 +225,7 @@ export default function UpcomingWidget({ items }: UpcomingWidgetProps) {
                 showPast ? 'bg-accent/15 text-accent' : 'text-muted-foreground hover:text-foreground hover:bg-white/5'
               )}
               title={showPast ? 'Hide past events' : 'Show past events'}
+              aria-label={showPast ? 'Hide past events' : 'Show past events'}
             >
               {showPast ? <Eye className="h-3.5 w-3.5" /> : <EyeOff className="h-3.5 w-3.5" />}
             </button>