Add settings, cloud places, and optional archive-content indexing.

Keep official clients in charge of sync while Explorer can group locations, persist UI prefs, and list zip/rar/7z members without extracting them.

Co-authored-by: Cursor <cursoragent@cursor.com>

tests/Explorer.Application.Tests/CloudProviderTests.cs

@@ -1,6 +1,8 @@
 using Explorer.Application;
 using Explorer.Domain;
 using Explorer.Plugin.Abstractions;
+using Explorer.Plugin.GoogleDrive;
+using Explorer.Plugin.Nextcloud;
 using Explorer.Plugin.OneDrive;
 using Microsoft.Extensions.Logging.Abstractions;
 
@@ -104,6 +106,111 @@ public class CloudProviderTests
         Assert.Equal("Dominique - Personal", merged[0].DisplayName);
         Assert.Equal(@"C:\Users\x\OneDrive - Contoso", merged[1].Path);
     }
+
+    [Fact]
+    public void Cloud_path_is_under_is_prefix_safe()
+    {
+        Assert.True(CloudPath.IsUnder(@"F:\OneDrive - wyniger", @"F:\OneDrive - wyniger\Obsidian\Notes"));
+        Assert.False(CloudPath.IsUnder(@"F:\OneDrive", @"F:\OneDrive - wyniger"));
+        Assert.True(CloudPath.IsUnder(@"J:\", @"J:\My Drive\Photos"));
+        Assert.Equal(@"J:\", CloudPath.NormalizePlace("j:"));
+        Assert.Equal(@"J:\", CloudPath.NormalizePlace(@"J:\"));
+    }
+
+    [Fact]
+    public void DriveFS_media_named_google_drive_becomes_a_place()
+    {
+        var places = DriveFsPreferenceReader.PlacesFromTables(
+            [
+                new("Games", @"D:\", 4),
+                new("Google Drive", @"J:\", 10),
+                new("MP3", @"G:\", 4)
+            ],
+            [
+                new("My Drive", @"My Drive", @"J:\My Drive", true)
+            ]);
+        Assert.Single(places);
+        Assert.Equal("googledrive", places[0].ProviderId);
+        Assert.Equal("Google Drive", places[0].DisplayName);
+        Assert.Equal(@"J:\", places[0].Path);
+    }
+
+    [Fact]
+    public void DriveFS_mirrored_folder_becomes_a_place_when_no_mount()
+    {
+        var places = DriveFsPreferenceReader.PlacesFromTables(
+            [new("Data", @"F:\", 4)],
+            [new("Photos", @"Photos", @"F:\Google Photos", false)]);
+        Assert.Single(places);
+        Assert.Equal("Google Drive - Photos", places[0].DisplayName);
+        Assert.Equal(@"F:\Google Photos", places[0].Path);
+    }
+
+    [Fact]
+    public void DriveFS_local_preference_db_exposes_configured_mount()
+    {
+        if (!File.Exists(DriveFsPreferenceReader.DefaultDatabasePath))
+        {
+            return;
+        }
+
+        var places = DriveFsPreferenceReader.ReadPlaces();
+        Assert.Contains(places, p => p.DisplayName == "Google Drive" && p.Path.Length >= 2);
+    }
+
+    [Theory]
+    [InlineData(@"C:\Users\x\My Drive", "Google Drive")]
+    [InlineData(@"G:\Shared drives", "Shared drives")]
+    [InlineData(@"D:\Work", "Google Drive - Work")]
+    public void Google_drive_place_label(string path, string expected)
+        => Assert.Equal(expected, GoogleDrivePlaceDiscovery.BuildLabel(path, null));
+
+    [Fact]
+    public void Nextcloud_parses_account_folders_from_cfg()
+    {
+        const string cfg = """
+            [Accounts]
+            0\url=https://cloud.example.com
+            0\displayName=Dominique Wyniger
+            0\Folders\1\localPath=F:/OneDrive - wyniger/Obsidian/Notes/
+            0\Folders\1\targetPath=/Notizen/Notes
+            0\Folders\1\virtualFilesMode=off
+            """;
+        var places = NextcloudPlaceDiscovery.ParseCfg(cfg);
+        Assert.Single(places);
+        Assert.Equal("nextcloud", places[0].ProviderId);
+        Assert.Equal(@"F:\OneDrive - wyniger\Obsidian\Notes", places[0].Path);
+        Assert.Equal("Nextcloud - Notes", places[0].DisplayName);
+    }
+
+    [Fact]
+    public void OneDrive_does_not_claim_google_drive_paths()
+    {
+        Assert.False(OneDriveStorageProvider.LooksLikeOneDrive(@"G:\My Drive\Photos"));
+        Assert.True(GoogleDriveStorageProvider.LooksLikeGoogleDrive(@"G:\My Drive\Photos"));
+    }
+
+    [Fact]
+    public void Discover_skips_missing_default_profile_folders()
+    {
+        var profile = Environment.GetFolderPath(Environment.SpecialFolder.UserProfile);
+        var google = GoogleDrivePlaceDiscovery.Discover();
+        var nextcloud = NextcloudPlaceDiscovery.Discover();
+        AssertMissingGuess(google, Path.Combine(profile, "Google Drive"));
+        AssertMissingGuess(google, Path.Combine(profile, "My Drive"));
+        AssertMissingGuess(nextcloud, Path.Combine(profile, "Nextcloud"));
+        AssertMissingGuess(nextcloud, Path.Combine(profile, "ownCloud"));
+    }
+
+    private static void AssertMissingGuess(IReadOnlyList<ProviderPlace> places, string path)
+    {
+        if (Directory.Exists(path))
+        {
+            return;
+        }
+
+        Assert.DoesNotContain(places, p => p.Path.Equals(path.TrimEnd('\\'), StringComparison.OrdinalIgnoreCase));
+    }
 }
 
 file static class CloudFilesNativeStates