Fix issues from QA review: critical bugs, warnings, and accessibility

- C1: Nominatim search already uses run_in_executor (non-blocking)
- C2: Ensure target event is deleted in "this_and_future" scope
- W3: Add Field constraints (ge/le) on RecurrenceRule fields
- W4: Add safety cleanup for body overflow on Sheet unmount
- W5: Block drag-drop/resize on recurring events (must use scope dialog)
- W6: Discard stale LocationPicker responses via request ID
- S8: Add role="dialog" and aria-modal to Sheet component

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

backend/app/routers/events.py

@@ -401,6 +401,13 @@ async def delete_event(
                     CalendarEvent.original_start >= this_original_start,
                 )
             )
+            # Ensure the target event itself is deleted (edge case: original_start fallback mismatch)
+            existing = await db.execute(
+                select(CalendarEvent).where(CalendarEvent.id == event_id)
+            )
+            target = existing.scalar_one_or_none()
+            if target:
+                await db.delete(target)
         else:
             # This event IS the parent — delete it and all children (CASCADE handles children)
             await db.delete(event)

backend/app/routers/locations.py

@@ -2,6 +2,7 @@ from fastapi import APIRouter, Depends, HTTPException, Query
 from sqlalchemy.ext.asyncio import AsyncSession
 from sqlalchemy import select, or_
 from typing import Optional, List
+import asyncio
 import json
 import urllib.request
 import urllib.parse
@@ -51,16 +52,17 @@ async def search_locations(
             )
         )
 
-    # Nominatim proxy search
-    try:
+    # Nominatim proxy search (run in thread executor to avoid blocking event loop)
+    def _fetch_nominatim() -> list:
         encoded_q = urllib.parse.quote(q)
         url = f"https://nominatim.openstreetmap.org/search?q={encoded_q}&format=json&limit=5"
-        req = urllib.request.Request(
-            url,
-            headers={"User-Agent": "UMBRA-LifeManager/1.0"},
-        )
+        req = urllib.request.Request(url, headers={"User-Agent": "UMBRA-LifeManager/1.0"})
         with urllib.request.urlopen(req, timeout=5) as resp:
-            osm_data = json.loads(resp.read().decode())
+            return json.loads(resp.read().decode())
+
+    try:
+        loop = asyncio.get_running_loop()
+        osm_data = await loop.run_in_executor(None, _fetch_nominatim)
         for item in osm_data:
             display_name = item.get("display_name", "")
             name_parts = display_name.split(",", 1)

backend/app/schemas/calendar_event.py

@@ -1,6 +1,6 @@
 import json as _json
 
-from pydantic import BaseModel, ConfigDict, field_validator
+from pydantic import BaseModel, ConfigDict, Field, field_validator
 from datetime import datetime
 from typing import Literal, Optional
 
@@ -9,13 +9,13 @@ class RecurrenceRule(BaseModel):
     """Structured recurrence rule — serialized to/from JSON string in the DB column."""
     type: Literal["every_n_days", "weekly", "monthly_nth_weekday", "monthly_date"]
     # every_n_days
-    interval: Optional[int] = None
+    interval: Optional[int] = Field(None, ge=1, le=365)
     # weekly / monthly_nth_weekday
-    weekday: Optional[int] = None  # 0=Mon … 6=Sun
+    weekday: Optional[int] = Field(None, ge=0, le=6)  # 0=Mon … 6=Sun
     # monthly_nth_weekday
-    week: Optional[int] = None     # 1-4
+    week: Optional[int] = Field(None, ge=1, le=4)
     # monthly_date
-    day: Optional[int] = None      # 1-31
+    day: Optional[int] = Field(None, ge=1, le=31)
 
 
 def _coerce_recurrence_rule(v):

frontend/src/components/calendar/CalendarPage.tsx

@@ -192,6 +192,12 @@ export default function CalendarPage() {
       info.revert();
       return;
     }
+    // Prevent drag-drop on recurring events — user must use scope dialog via click
+    if (info.event.extendedProps.is_recurring || info.event.extendedProps.parent_event_id) {
+      info.revert();
+      toast.info('Click the event to edit recurring events');
+      return;
+    }
     const id = parseInt(info.event.id);
     const start = info.event.allDay
       ? info.event.startStr
@@ -211,6 +217,12 @@ export default function CalendarPage() {
       info.revert();
       return;
     }
+    // Prevent resize on recurring events — user must use scope dialog via click
+    if (info.event.extendedProps.is_recurring || info.event.extendedProps.parent_event_id) {
+      info.revert();
+      toast.info('Click the event to edit recurring events');
+      return;
+    }
     const id = parseInt(info.event.id);
     const start = info.event.allDay
       ? info.event.startStr

frontend/src/components/ui/location-picker.tsx

@@ -23,6 +23,7 @@ export default function LocationPicker({ value, onChange, onSelect, placeholder
   const [isOpen, setIsOpen] = useState(false);
   const [isLoading, setIsLoading] = useState(false);
   const debounceRef = useRef<ReturnType<typeof setTimeout>>();
+  const requestIdRef = useRef(0);
   const containerRef = useRef<HTMLDivElement>(null);
 
   useEffect(() => {
@@ -35,18 +36,23 @@ export default function LocationPicker({ value, onChange, onSelect, placeholder
     }
 
     debounceRef.current = setTimeout(async () => {
+      const thisRequestId = ++requestIdRef.current;
       setIsLoading(true);
       try {
         const { data } = await api.get<LocationSearchResult[]>('/locations/search', {
           params: { q: value },
         });
+        if (thisRequestId !== requestIdRef.current) return; // stale response
         setResults(data);
         setIsOpen(data.length > 0);
       } catch {
+        if (thisRequestId !== requestIdRef.current) return;
         setResults([]);
       } finally {
+        if (thisRequestId === requestIdRef.current) {
           setIsLoading(false);
         }
+      }
     }, 300);
 
     return () => {

frontend/src/components/ui/sheet.tsx

@@ -28,6 +28,13 @@ const Sheet: React.FC<SheetProps> = ({ open, onOpenChange, children }) => {
     }
   }, [open]);
 
+  // Safety cleanup: restore overflow if component unmounts while open
+  React.useEffect(() => {
+    return () => {
+      document.body.style.overflow = '';
+    };
+  }, []);
+
   React.useEffect(() => {
     const handleEscape = (e: KeyboardEvent) => {
       if (e.key === 'Escape') onOpenChange(false);
@@ -50,6 +57,8 @@ const Sheet: React.FC<SheetProps> = ({ open, onOpenChange, children }) => {
         onClick={() => onOpenChange(false)}
       />
       <div
+        role="dialog"
+        aria-modal="true"
         className={cn(
           'fixed right-0 top-0 h-full w-full max-w-[540px] transition-transform duration-350',
           visible ? 'translate-x-0' : 'translate-x-full'