fix(web): remove error notifications for location geocoding failures

Remove disruptive error toasts when reverse geocoding or geolocation fails.
Instead, silently fall back to using coordinates as the location placeholder.
This improves UX for users in regions where OpenStreetMap is restricted
(e.g., China) or when CSP blocks external API calls.

Fixes #5198, #5197

🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>

web/src/components/MemoEditor/ActionButton/LocationSelector.tsx

 import { LatLng } from "leaflet";
 import { MapPinIcon, XIcon } from "lucide-react";
 import { useEffect, useState } from "react";
-import toast from "react-hot-toast";
 import LeafletMap from "@/components/LeafletMap";
 import { Button } from "@/components/ui/button";
 import { Input } from "@/components/ui/input";
@@ -48,10 +47,9 @@ const LocationSelector = (props: Props) => {
 
   useEffect(() => {
     if (popoverOpen && !props.location) {
-      const handleError = (error: any, errorMessage: string) => {
+      const handleError = (error: any) => {
         setState((prev) => ({ ...prev, initialized: true }));
-        toast.error(errorMessage);
-        console.error(error);
+        console.error("Geolocation error:", error);
       };
 
       if (navigator.geolocation) {
@@ -68,11 +66,11 @@ const LocationSelector = (props: Props) => {
             }));
           },
           (error) => {
-            handleError(error, "Failed to get current position");
+            handleError(error);
           },
         );
       } else {
-        handleError("Geolocation is not supported by this browser.", "Geolocation is not supported by this browser.");
+        handleError("Geolocation is not supported by this browser.");
       }
     }
   }, [popoverOpen, props.location]);
@@ -91,16 +89,29 @@ const LocationSelector = (props: Props) => {
     }
 
     // Fetch reverse geocoding data.
-    fetch(`https://nominatim.openstreetmap.org/reverse?lat=${state.position.lat}&lon=${state.position.lng}&format=json`)
+    const lat = state.position.lat;
+    const lng = state.position.lng;
+
+    fetch(`https://nominatim.openstreetmap.org/reverse?lat=${lat}&lon=${lng}&format=json`)
       .then((response) => response.json())
       .then((data) => {
         if (data && data.display_name) {
           setState((prev) => ({ ...prev, placeholder: data.display_name }));
+        } else {
+          // Fallback to coordinates if no display name
+          setState((prev) => ({
+            ...prev,
+            placeholder: `${lat.toFixed(6)}, ${lng.toFixed(6)}`,
+          }));
         }
       })
       .catch((error) => {
-        toast.error("Failed to fetch reverse geocoding data");
+        // Silent fallback: use coordinates as placeholder when geocoding fails
         console.error("Failed to fetch reverse geocoding data:", error);
+        setState((prev) => ({
+          ...prev,
+          placeholder: `${lat.toFixed(6)}, ${lng.toFixed(6)}`,
+        }));
       });
   }, [state.position]);