Tagebuch: Geolocation + Reverse-Geocoding beim Anlegen

- OneShotLocation beim Sheet-Öffnen, Toggle 'Standort verwenden' (Default an)
- CLGeocoder reverseGeocodeLocation (de_DE-Locale) füllt locationName aus
  Placemark.name, Fallback thoroughfare + locality. User kann überschreiben.
- gps_lat/gps_lon werden mit dem Eintrag gesendet, wenn Toggle an — die PWA
  rendert daraus die POI-Karte im Tagebuch.

BanYaroGo/Views/AddDiaryEntrySheet.swift

@@ -1,5 +1,6 @@
 import SwiftUI
 import PhotosUI
+import CoreLocation
 
 struct AddDiaryEntrySheet: View {
     let dogId: Int
@@ -17,6 +18,10 @@ struct AddDiaryEntrySheet: View {
     @State private var photoSelection: [PhotosPickerItem] = []
     @State private var photoData: [Data] = []
 
+    @State private var location = OneShotLocation()
+    @State private var attachLocation = true
+    @State private var isReverseGeocoding = false
+
     @State private var saveState: SaveState = .idle
     @State private var errorMessage: String?
 
@@ -42,12 +47,55 @@ struct AddDiaryEntrySheet: View {
                 }
                 Section {
                     Toggle("Meilenstein", isOn: $isMilestone)
-                    TextField("Ort (optional)", text: $locationName)
                     TextField("Tags (komma-getrennt)", text: $tagsInput)
                         .textInputAutocapitalization(.never)
                         .autocorrectionDisabled()
                 }
 
+                Section {
+                    Toggle(isOn: $attachLocation) {
+                        Label("Standort verwenden", systemImage: "location.fill")
+                    }
+                    if attachLocation {
+                        if let coord = location.coordinate {
+                            HStack {
+                                Image(systemName: "mappin.and.ellipse")
+                                    .foregroundStyle(Color.accentColor)
+                                VStack(alignment: .leading, spacing: 2) {
+                                    if !locationName.isEmpty {
+                                        Text(locationName).font(.subheadline)
+                                    } else if isReverseGeocoding {
+                                        Text("Suche Ortsbezeichnung…")
+                                            .font(.caption)
+                                            .foregroundStyle(.secondary)
+                                    } else {
+                                        Text("Ort wird mitgespeichert")
+                                            .font(.subheadline)
+                                    }
+                                    Text(String(format: "%.5f, %.5f", coord.latitude, coord.longitude))
+                                        .font(.caption2.monospacedDigit())
+                                        .foregroundStyle(.tertiary)
+                                }
+                            }
+                        } else if location.error != nil {
+                            Label("Standort nicht verfügbar — wird ohne gespeichert", systemImage: "location.slash")
+                                .font(.caption)
+                                .foregroundStyle(.secondary)
+                        } else {
+                            HStack {
+                                ProgressView()
+                                Text("Hole Standort…").font(.caption).foregroundStyle(.secondary)
+                            }
+                        }
+                        TextField("Ort überschreiben (optional)", text: $locationName)
+                    }
+                } header: {
+                    Text("Standort")
+                } footer: {
+                    Text("Der Standort wird zusammen mit dem Eintrag gespeichert — banyaro.app rendert daraus deine POI-Karte.")
+                        .font(.caption2)
+                }
+
                 Section {
                     PhotosPicker(
                         selection: $photoSelection,
@@ -93,10 +141,37 @@ struct AddDiaryEntrySheet: View {
             .onChange(of: photoSelection) { _, items in
                 Task { await loadPhotos(from: items) }
             }
+            .task { location.request() }
+            .onChange(of: location.coordinate?.latitude) { _, _ in
+                guard let coord = location.coordinate, locationName.isEmpty else { return }
+                Task { await reverseGeocode(coord) }
+            }
             .interactiveDismissDisabled(saveState != .idle)
         }
     }
 
+    private func reverseGeocode(_ coord: CLLocationCoordinate2D) async {
+        isReverseGeocoding = true
+        defer { isReverseGeocoding = false }
+        let geocoder = CLGeocoder()
+        let loc = CLLocation(latitude: coord.latitude, longitude: coord.longitude)
+        do {
+            let placemarks = try await geocoder.reverseGeocodeLocation(loc, preferredLocale: Locale(identifier: "de_DE"))
+            guard let p = placemarks.first else { return }
+            // Sample: "Café Kaiser, Berlin" — name first, then locality fallback
+            if let name = p.name, !name.isEmpty {
+                locationName = name
+                return
+            }
+            var parts: [String] = []
+            if let street = p.thoroughfare { parts.append(street) }
+            if let city = p.locality { parts.append(city) }
+            if !parts.isEmpty { locationName = parts.joined(separator: ", ") }
+        } catch {
+            print("Reverse geocode failed: \(error)")
+        }
+    }
+
     @ViewBuilder
     private var saveToolbarItem: some View {
         switch saveState {
@@ -132,14 +207,15 @@ struct AddDiaryEntrySheet: View {
             .map { $0.trimmingCharacters(in: .whitespacesAndNewlines) }
             .filter { !$0.isEmpty }
 
+        let coord = attachLocation ? location.coordinate : nil
         let body = DiaryCreateBody(
             datum: formatter.string(from: date),
             typ: isMilestone ? "meilenstein" : "eintrag",
             titel: titel.trimmingCharacters(in: .whitespaces).isEmpty ? nil : titel.trimmingCharacters(in: .whitespaces),
             text: text.trimmingCharacters(in: .whitespaces).isEmpty ? nil : text.trimmingCharacters(in: .whitespacesAndNewlines),
             tags: tags.isEmpty ? nil : tags,
-            gpsLat: nil,
-            gpsLon: nil,
+            gpsLat: coord?.latitude,
+            gpsLon: coord?.longitude,
             locationName: locationName.trimmingCharacters(in: .whitespaces).isEmpty ? nil : locationName,
             isMilestone: isMilestone
         )