Added backups of all data, restorable on another computer (#1008)

Co-authored-by: Thorsten Sommer <SommerEngineering@users.noreply.github.com>

app/MindWork AI Studio/Settings/ChatTemplate.cs

@@ -421,11 +421,7 @@ public record ChatTemplate(
         }
 
         var combinedPath = Path.GetFullPath(Path.Combine(pluginRoot, relativePath));
-        var pluginRootWithSeparator = pluginRoot.EndsWith(Path.DirectorySeparatorChar)
-            ? pluginRoot
-            : pluginRoot + Path.DirectorySeparatorChar;
-        var comparison = OperatingSystem.IsWindows() ? StringComparison.OrdinalIgnoreCase : StringComparison.Ordinal;
-        if (!combinedPath.StartsWith(pluginRootWithSeparator, comparison))
+        if (!PathTools.IsInsideDirectory(pluginRoot, combinedPath))
         {
             LOGGER.LogWarning("The relative FileAttachments entry {AttachmentNum} in chat template {IdxChatTemplate} points outside of the plugin folder and will be ignored.", attachmentNum, idx);
             return false;

app/MindWork AI Studio/Settings/DataModel/Data.cs

@@ -116,6 +116,16 @@ public sealed class Data
     /// </remarks>
     public List<string> AppliedEnterpriseAssistantActivations { get; set; } = [];
 
+    /// <summary>
+    /// Whether AI Studio already stored the chats and the settings once more, so that every path below
+    /// the data directory in them is relative.
+    /// </summary>
+    /// <remarks>
+    /// Compatibility shim, see documentation/compatibility-shims/2026-10-relative-data-paths.md.
+    /// Remove after 2027-04-14.
+    /// </remarks>
+    public bool StoredDataPathsAreRelative { get; set; }
+
     /// <summary>
     /// The next provider number to use.
     /// </summary>

app/MindWork AI Studio/Settings/DataModel/DataApp.cs

@@ -219,6 +219,24 @@ public sealed class DataApp(Expression<Func<Data, DataApp>>? configSelection = n
     /// </summary>
     public bool AllowUserToSharePlugins { get; set; } = ManagedConfiguration.Register(configSelection, n => n.AllowUserToSharePlugins, true);
 
+    /// <summary>
+    /// Should the user be allowed to back up the data of AI Studio into a file?
+    /// </summary>
+    /// <remarks>
+    /// A backup holds chats and other confidential content in a single file, which can leave the
+    /// computer on any stick or cloud drive. Secrets never go into it.
+    /// </remarks>
+    public bool AllowUserToBackUpData { get; set; } = ManagedConfiguration.Register(configSelection, n => n.AllowUserToBackUpData, true);
+
+    /// <summary>
+    /// Should the user be allowed to restore the data of AI Studio from a backup file, or to add the chats of one?
+    /// </summary>
+    /// <remarks>
+    /// A backup brings along everything its chats and settings name, including the locations of
+    /// attached documents and of local data sources, which are read again afterward.
+    /// </remarks>
+    public bool AllowUserToRestoreData { get; set; } = ManagedConfiguration.Register(configSelection, n => n.AllowUserToRestoreData, true);
+
     /// <summary>
     /// Should administration settings be visible in the UI?
     /// </summary>

app/MindWork AI Studio/Settings/EmbeddingProvider.cs

@@ -22,7 +22,7 @@ public sealed record EmbeddingProvider(
     Guid EnterpriseConfigurationPluginId = default,
     string Hostname = "http://localhost:1234",
     Host Host = Host.NONE,
-    string TokenizerPath = "",
+    [property: JsonConverter(typeof(DataDirectoryRelativePathConverter))] string TokenizerPath = "",
     string TokenizerFingerprint = "",
     int EmbeddingBatchSize = 0,
     int TokenLimit = 0,

app/MindWork AI Studio/Settings/PluginIconFile.cs

@@ -56,7 +56,7 @@ internal static class PluginIconFile
             return false;
         }
 
-        if (!IsInsideDirectory(pluginRoot, resolvedPath))
+        if (!PathTools.IsInsideDirectory(pluginRoot, resolvedPath))
         {
             issue = "The icon path points outside of the configuration plugin directory.";
             return false;
@@ -108,18 +108,10 @@ internal static class PluginIconFile
             currentPath = Path.Combine(currentPath, segment);
             FileSystemInfo pathInfo = Directory.Exists(currentPath) ? new DirectoryInfo(currentPath) : new FileInfo(currentPath);
             var finalTarget = pathInfo.ResolveLinkTarget(true);
-            if (finalTarget is not null && !IsInsideDirectory(rootDirectory, finalTarget.FullName))
+            if (finalTarget is not null && !PathTools.IsInsideDirectory(rootDirectory, finalTarget.FullName))
                 return false;
         }
 
         return true;
     }
-
-    private static bool IsInsideDirectory(string rootDirectory, string path)
-    {
-        var root = Path.GetFullPath(rootDirectory).TrimEnd(Path.DirectorySeparatorChar, Path.AltDirectorySeparatorChar) + Path.DirectorySeparatorChar;
-        var target = Path.GetFullPath(path);
-        var comparison = OperatingSystem.IsWindows() ? StringComparison.OrdinalIgnoreCase : StringComparison.Ordinal;
-        return target.StartsWith(root, comparison);
-    }
 }

app/MindWork AI Studio/Settings/Provider.cs

@@ -36,7 +36,7 @@ public sealed record Provider(
     Host Host = Host.NONE,
     HFInferenceProvider HFInferenceProvider = HFInferenceProvider.NONE,
     string AdditionalJsonApiParameters = "",
-    string TokenizerPath = "",
+    [property: JsonConverter(typeof(DataDirectoryRelativePathConverter))] string TokenizerPath = "",
     ProviderCapabilityOverrides? CapabilityOverrides = null,
     bool AllowUserProvidedAPIKey = false,
     string CustomIconDataUrl = "") : ConfigurationBaseObject, ISecretId, IUserProvidedAPIKey