postit: preserve manual rdv address with map suggestion

src/PostIt/PostIt.Tests/BillingCommandPageViewModelTests.cs

@@ -135,6 +135,50 @@ public class BillingCommandPageViewModelTests
         Assert.Contains("Position sélectionnée", vm.StatusMessage, StringComparison.OrdinalIgnoreCase);
     }
 
+    [Fact]
+    public void ApplyResolvedAddress_populates_empty_address_directly()
+    {
+        var api = new RecordingApi();
+        var client = new BillingApiClient(api, "https://business.example/api/v1/");
+        var vm =
+            new CommandFormSummary { Id = 12, ActionName = "Rdv", Title = "Rendez-vous" }
+            .CreateCommandPageViewModel(
+                new ActivityInfo { Code = "dev", Name = "Développement" },
+                new ActivityUserDisplayItem { PerformerId = "perf-1", UserName = "Alice" },
+                client) as RdvViewModel;
+
+        vm!.Address = string.Empty;
+        vm.ApplyResolvedAddress("10 rue de Rivoli, 75001 Paris");
+
+        Assert.Equal("10 rue de Rivoli, 75001 Paris", vm.Address);
+        Assert.False(vm.HasSuggestedAddress);
+    }
+
+    [Fact]
+    public void ApplyResolvedAddress_preserves_manual_address_and_exposes_suggestion()
+    {
+        var api = new RecordingApi();
+        var client = new BillingApiClient(api, "https://business.example/api/v1/");
+        var vm =
+            new CommandFormSummary { Id = 12, ActionName = "Rdv", Title = "Rendez-vous" }
+            .CreateCommandPageViewModel(
+                new ActivityInfo { Code = "dev", Name = "Développement" },
+                new ActivityUserDisplayItem { PerformerId = "perf-1", UserName = "Alice" },
+                client) as RdvViewModel;
+
+        vm!.Address = "Saisie manuelle";
+        vm.ApplyResolvedAddress("10 rue de Rivoli, 75001 Paris");
+
+        Assert.Equal("Saisie manuelle", vm.Address);
+        Assert.True(vm.HasSuggestedAddress);
+        Assert.Equal("10 rue de Rivoli, 75001 Paris", vm.SuggestedAddress);
+
+        vm.ApplySuggestedAddressCommand.Execute(null);
+
+        Assert.Equal("10 rue de Rivoli, 75001 Paris", vm.Address);
+        Assert.False(vm.HasSuggestedAddress);
+    }
+
     [Fact]
     public async Task InitializeAsync_loads_prestations_for_brush_and_submit_posts_selected_prestation()
     {