feat: storage provider abstraction + FTP provider

Atypical.VirtualFileSystem.sln

@@ -23,6 +23,14 @@ Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Atypical.VirtualFileSystem.
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Atypical.VirtualFileSystem.GitHub.Tests", "tests\Atypical.VirtualFileSystem.GitHub.Tests\Atypical.VirtualFileSystem.GitHub.Tests.csproj", "{31971414-5519-4149-B5C0-C88454EBE7AD}"
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Atypical.VirtualFileSystem.Providers.Abstractions", "src\Atypical.VirtualFileSystem.Providers.Abstractions\Atypical.VirtualFileSystem.Providers.Abstractions.csproj", "{B2E9D21C-6C01-4F28-AF7C-2EF16148E964}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Atypical.VirtualFileSystem.Providers.Abstractions.Tests", "tests\Atypical.VirtualFileSystem.Providers.Abstractions.Tests\Atypical.VirtualFileSystem.Providers.Abstractions.Tests.csproj", "{2E8D3BE3-F419-46B1-BBD3-FC5F753261D0}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Atypical.VirtualFileSystem.Ftp", "src\Atypical.VirtualFileSystem.Ftp\Atypical.VirtualFileSystem.Ftp.csproj", "{9601A06C-4C43-4E68-8576-F92BBFFEA73B}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Atypical.VirtualFileSystem.Ftp.Tests", "tests\Atypical.VirtualFileSystem.Ftp.Tests\Atypical.VirtualFileSystem.Ftp.Tests.csproj", "{37D1D6B7-C4E5-44EC-96C1-C2C6CDB900C5}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -117,6 +125,54 @@ Global
 		{31971414-5519-4149-B5C0-C88454EBE7AD}.Release|x64.Build.0 = Release|Any CPU
 		{31971414-5519-4149-B5C0-C88454EBE7AD}.Release|x86.ActiveCfg = Release|Any CPU
 		{31971414-5519-4149-B5C0-C88454EBE7AD}.Release|x86.Build.0 = Release|Any CPU
+		{B2E9D21C-6C01-4F28-AF7C-2EF16148E964}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{B2E9D21C-6C01-4F28-AF7C-2EF16148E964}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{B2E9D21C-6C01-4F28-AF7C-2EF16148E964}.Debug|x64.ActiveCfg = Debug|Any CPU
+		{B2E9D21C-6C01-4F28-AF7C-2EF16148E964}.Debug|x64.Build.0 = Debug|Any CPU
+		{B2E9D21C-6C01-4F28-AF7C-2EF16148E964}.Debug|x86.ActiveCfg = Debug|Any CPU
+		{B2E9D21C-6C01-4F28-AF7C-2EF16148E964}.Debug|x86.Build.0 = Debug|Any CPU
+		{B2E9D21C-6C01-4F28-AF7C-2EF16148E964}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{B2E9D21C-6C01-4F28-AF7C-2EF16148E964}.Release|Any CPU.Build.0 = Release|Any CPU
+		{B2E9D21C-6C01-4F28-AF7C-2EF16148E964}.Release|x64.ActiveCfg = Release|Any CPU
+		{B2E9D21C-6C01-4F28-AF7C-2EF16148E964}.Release|x64.Build.0 = Release|Any CPU
+		{B2E9D21C-6C01-4F28-AF7C-2EF16148E964}.Release|x86.ActiveCfg = Release|Any CPU
+		{B2E9D21C-6C01-4F28-AF7C-2EF16148E964}.Release|x86.Build.0 = Release|Any CPU
+		{2E8D3BE3-F419-46B1-BBD3-FC5F753261D0}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{2E8D3BE3-F419-46B1-BBD3-FC5F753261D0}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{2E8D3BE3-F419-46B1-BBD3-FC5F753261D0}.Debug|x64.ActiveCfg = Debug|Any CPU
+		{2E8D3BE3-F419-46B1-BBD3-FC5F753261D0}.Debug|x64.Build.0 = Debug|Any CPU
+		{2E8D3BE3-F419-46B1-BBD3-FC5F753261D0}.Debug|x86.ActiveCfg = Debug|Any CPU
+		{2E8D3BE3-F419-46B1-BBD3-FC5F753261D0}.Debug|x86.Build.0 = Debug|Any CPU
+		{2E8D3BE3-F419-46B1-BBD3-FC5F753261D0}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{2E8D3BE3-F419-46B1-BBD3-FC5F753261D0}.Release|Any CPU.Build.0 = Release|Any CPU
+		{2E8D3BE3-F419-46B1-BBD3-FC5F753261D0}.Release|x64.ActiveCfg = Release|Any CPU
+		{2E8D3BE3-F419-46B1-BBD3-FC5F753261D0}.Release|x64.Build.0 = Release|Any CPU
+		{2E8D3BE3-F419-46B1-BBD3-FC5F753261D0}.Release|x86.ActiveCfg = Release|Any CPU
+		{2E8D3BE3-F419-46B1-BBD3-FC5F753261D0}.Release|x86.Build.0 = Release|Any CPU
+		{9601A06C-4C43-4E68-8576-F92BBFFEA73B}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{9601A06C-4C43-4E68-8576-F92BBFFEA73B}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{9601A06C-4C43-4E68-8576-F92BBFFEA73B}.Debug|x64.ActiveCfg = Debug|Any CPU
+		{9601A06C-4C43-4E68-8576-F92BBFFEA73B}.Debug|x64.Build.0 = Debug|Any CPU
+		{9601A06C-4C43-4E68-8576-F92BBFFEA73B}.Debug|x86.ActiveCfg = Debug|Any CPU
+		{9601A06C-4C43-4E68-8576-F92BBFFEA73B}.Debug|x86.Build.0 = Debug|Any CPU
+		{9601A06C-4C43-4E68-8576-F92BBFFEA73B}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{9601A06C-4C43-4E68-8576-F92BBFFEA73B}.Release|Any CPU.Build.0 = Release|Any CPU
+		{9601A06C-4C43-4E68-8576-F92BBFFEA73B}.Release|x64.ActiveCfg = Release|Any CPU
+		{9601A06C-4C43-4E68-8576-F92BBFFEA73B}.Release|x64.Build.0 = Release|Any CPU
+		{9601A06C-4C43-4E68-8576-F92BBFFEA73B}.Release|x86.ActiveCfg = Release|Any CPU
+		{9601A06C-4C43-4E68-8576-F92BBFFEA73B}.Release|x86.Build.0 = Release|Any CPU
+		{37D1D6B7-C4E5-44EC-96C1-C2C6CDB900C5}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{37D1D6B7-C4E5-44EC-96C1-C2C6CDB900C5}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{37D1D6B7-C4E5-44EC-96C1-C2C6CDB900C5}.Debug|x64.ActiveCfg = Debug|Any CPU
+		{37D1D6B7-C4E5-44EC-96C1-C2C6CDB900C5}.Debug|x64.Build.0 = Debug|Any CPU
+		{37D1D6B7-C4E5-44EC-96C1-C2C6CDB900C5}.Debug|x86.ActiveCfg = Debug|Any CPU
+		{37D1D6B7-C4E5-44EC-96C1-C2C6CDB900C5}.Debug|x86.Build.0 = Debug|Any CPU
+		{37D1D6B7-C4E5-44EC-96C1-C2C6CDB900C5}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{37D1D6B7-C4E5-44EC-96C1-C2C6CDB900C5}.Release|Any CPU.Build.0 = Release|Any CPU
+		{37D1D6B7-C4E5-44EC-96C1-C2C6CDB900C5}.Release|x64.ActiveCfg = Release|Any CPU
+		{37D1D6B7-C4E5-44EC-96C1-C2C6CDB900C5}.Release|x64.Build.0 = Release|Any CPU
+		{37D1D6B7-C4E5-44EC-96C1-C2C6CDB900C5}.Release|x86.ActiveCfg = Release|Any CPU
+		{37D1D6B7-C4E5-44EC-96C1-C2C6CDB900C5}.Release|x86.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE
@@ -129,5 +185,9 @@ Global
 		{A1B2C3D4-E5F6-7890-1234-567890ABCDEF} = {10E2E10B-AB65-4800-93ED-CDB737917154}
 		{0F803EA9-AD74-46E3-9404-5D536E0F262C} = {BA11C821-EFDE-4714-A0DE-B7D4D93CE336}
 		{31971414-5519-4149-B5C0-C88454EBE7AD} = {10E2E10B-AB65-4800-93ED-CDB737917154}
+		{B2E9D21C-6C01-4F28-AF7C-2EF16148E964} = {BA11C821-EFDE-4714-A0DE-B7D4D93CE336}
+		{2E8D3BE3-F419-46B1-BBD3-FC5F753261D0} = {10E2E10B-AB65-4800-93ED-CDB737917154}
+		{9601A06C-4C43-4E68-8576-F92BBFFEA73B} = {BA11C821-EFDE-4714-A0DE-B7D4D93CE336}
+		{37D1D6B7-C4E5-44EC-96C1-C2C6CDB900C5} = {10E2E10B-AB65-4800-93ED-CDB737917154}
 	EndGlobalSection
 EndGlobal

CLAUDE.md

@@ -60,6 +60,13 @@ IRootNode (vfs://)
 └── IFileNode (contains Content string)
 ```
 
+### Storage Providers
+External backends are plugged in behind a provider abstraction (the `Core` VFS itself stays storage-agnostic):
+- `Atypical.VirtualFileSystem.Providers.Abstractions` defines `IStorageProvider` (`ImportAsync`/`ReadFileAsync`/`WriteChangesAsync`/`GetAccountInfoAsync`), `IStorageProviderAuth`, `ProviderCapabilities`, and neutral records (`ProviderLoadOptions/Result`, `ProviderFileChange`, `CommitContext`, `ProviderFileMetadata`, `AuthRequest/Result`).
+- Branch/PR/fork are NOT base-interface methods — they are `ProviderCapabilities` flags plus `CommitContext` fields, so capable providers (GitHub) honor them and others (FTP) ignore them.
+- Implementations: `Atypical.VirtualFileSystem.GitHub` (`GitHubStorageProvider`, wraps the existing Octokit loader/write service via adapters — Token auth, supports branches/PR/fork) and `Atypical.VirtualFileSystem.Ftp` (`FtpStorageProvider` over FluentFTP — Credentials auth, read+write/overwrite, no branches/PR).
+- The Blazor app selects the active provider via `IStorageProviderRegistry` and drives its UI (import dialog fields, "submit changes") from `ProviderCapabilities`; FTP credentials and the GitHub PAT are persisted encrypted via `ProtectedLocalStorage`.
+
 ### Path System
 - `VFSRootPath` - Root directory (vfs://)
 - `VFSDirectoryPath` - Directory paths with case-insensitive comparison

docs/superpowers/plans/2026-06-02-storage-providers-foundation-ftp.md

@@ -740,7 +740,7 @@ public sealed class GitHubStorageProvider : IStorageProvider
 
     public async Task<ProviderLoadResult> ImportAsync(IVirtualFileSystem vfs, ProviderLoadOptions options, CancellationToken cancellationToken = default)
     {
-        // RemoteRoot for GitHub is "owner/repo[/subpath]"; parse owner/repo and pass subpath via TargetPath.
+        // RemoteRoot for GitHub is "owner/repo[/subpath]"; parse owner/repo and pass subpath via the loader's SubPath (the remote filter), NOT TargetPath (the VFS destination).
         var (owner, repo, subPath) = ParseRemoteRoot(options.RemoteRoot);
         var ghOptions = GitHubProviderAdapters.ToGitHubLoaderOptions(options with { RemoteRoot = subPath }, _auth.Token);
         var result = await _loader.LoadRepositoryAsync(vfs, owner, repo, ghOptions, cancellationToken);

src/Atypical.VirtualFileSystem.DemoBlazorApp/Atypical.VirtualFileSystem.DemoBlazorApp.csproj

@@ -13,6 +13,8 @@
   <ItemGroup>
     <ProjectReference Include="../Atypical.VirtualFileSystem.Core/Atypical.VirtualFileSystem.Core.csproj" />
     <ProjectReference Include="../Atypical.VirtualFileSystem.GitHub/Atypical.VirtualFileSystem.GitHub.csproj" />
+    <ProjectReference Include="../Atypical.VirtualFileSystem.Providers.Abstractions/Atypical.VirtualFileSystem.Providers.Abstractions.csproj" />
+    <ProjectReference Include="../Atypical.VirtualFileSystem.Ftp/Atypical.VirtualFileSystem.Ftp.csproj" />
   </ItemGroup>
 
   <!-- Tailwind CSS Build -->

src/Atypical.VirtualFileSystem.DemoBlazorApp/Components/Dialogs/CreatePullRequestDialog.razor

@@ -1,10 +1,12 @@
-@* Create Pull Request Dialog *@
+@* Capability-driven "Submit changes" dialog (PR for GitHub, upload for FTP) *@
 @inject GitHubPendingChangesService PendingChangesService
 @inject GitHubAuthService AuthService
 @inject ToastService Toast
+@inject StoragePendingChangesService StorageSubmit
+@inject IStorageProviderRegistry Registry
 @implements IDisposable
 
-<Modal @bind-IsOpen="IsOpen" Title="Create Pull Request" Size="xl" CloseOnBackdropClick="@(!_isCreating)">
+<Modal @bind-IsOpen="IsOpen" Title="@DialogTitle" Size="xl" CloseOnBackdropClick="@(!_isCreating)">
     <ChildContent>
         @if (_result is not null && _result.Success)
         {
@@ -93,6 +95,51 @@
                 </div>
             </div>
         }
+        else if (!SupportsPullRequests)
+        {
+            @* Non-PR provider (e.g. FTP): simple upload confirmation *@
+            <div class="space-y-4">
+                <div class="bg-blue-50 border border-blue-200 rounded-lg p-3">
+                    <div class="flex gap-2">
+                        <svg class="w-4 h-4 text-blue-500 flex-shrink-0 mt-0.5" fill="none" viewBox="0 0 24 24" stroke-width="1.5" stroke="currentColor">
+                            <path stroke-linecap="round" stroke-linejoin="round" d="m11.25 11.25.041-.02a.75.75 0 0 1 1.063.852l-.708 2.836a.75.75 0 0 0 1.063.853l.041-.021M21 12a9 9 0 1 1-18 0 9 9 0 0 1 18 0Zm-9-3.75h.008v.008H12V8.25Z" />
+                        </svg>
+                        <span class="text-sm text-blue-700">
+                            @Registry.Active.DisplayName uploads changes directly to the remote — no pull request is created.
+                        </span>
+                    </div>
+                </div>
+
+                @if (_uploadChanges.Count == 0)
+                {
+                    <div class="bg-amber-50 border border-amber-200 rounded-lg p-3">
+                        <div class="flex gap-2">
+                            <svg class="w-4 h-4 text-amber-500 flex-shrink-0 mt-0.5" fill="none" viewBox="0 0 24 24" stroke-width="1.5" stroke="currentColor">
+                                <path stroke-linecap="round" stroke-linejoin="round" d="M12 9v3.75m-9.303 3.376c-.866 1.5.217 3.374 1.948 3.374h14.71c1.73 0 2.813-1.874 1.948-3.374L13.949 3.378c-.866-1.5-3.032-1.5-3.898 0L2.697 16.126ZM12 15.75h.007v.008H12v-.008Z" />
+                            </svg>
+                            <span class="text-sm text-amber-700">
+                                No tracked changes are available to upload for this provider yet.
+                            </span>
+                        </div>
+                    </div>
+                }
+                else
+                {
+                    <label class="block text-sm font-medium text-gray-700 mb-2">
+                        Files to upload (@_uploadChanges.Count)
+                    </label>
+                    <div class="border border-gray-200 rounded-lg max-h-48 overflow-y-auto">
+                        @foreach (var change in _uploadChanges)
+                        {
+                            <div class="flex items-center gap-2 px-3 py-2 border-b border-gray-100 last:border-b-0 text-sm">
+                                <span class="text-gray-700 truncate flex-1" title="@change.RemotePath">@change.RemotePath</span>
+                                <span class="text-xs text-gray-400">@change.Kind</span>
+                            </div>
+                        }
+                    </div>
+                }
+            </div>
+        }
         else
         {
             @* Input Form *@
@@ -223,6 +270,16 @@
         {
             <span class="text-sm text-gray-500">Creating pull request...</span>
         }
+        else if (!SupportsPullRequests)
+        {
+            <Button Variant="ghost" OnClick="Close">Cancel</Button>
+            <Button Variant="primary"
+                    OnClick="UploadChanges"
+                    Disabled="@(_uploadChanges.Count == 0)"
+                    Icon="M3 16.5v2.25A2.25 2.25 0 0 0 5.25 21h13.5A2.25 2.25 0 0 0 21 18.75V16.5m-13.5-9L12 3m0 0 4.5 4.5M12 3v13.5">
+                Upload changes
+            </Button>
+        }
         else
         {
             <Button Variant="ghost" OnClick="Close">Cancel</Button>
@@ -255,6 +312,15 @@
     private (string Owner, string Repository)? _repositoryInfo;
     private bool _wasOpen;
 
+    // Non-PR (upload) provider state.
+    private List<ProviderFileChange> _uploadChanges = new();
+
+    // Capability-driven view selectors.
+    private bool SupportsPullRequests => StorageSubmit.SupportsPullRequests;
+    private string DialogTitle => SupportsPullRequests
+        ? "Create Pull Request"
+        : $"Upload changes to {Registry.Active.DisplayName}";
+
     private bool CanCreate => AuthService.IsAuthenticated
                               && !string.IsNullOrWhiteSpace(_title)
                               && !string.IsNullOrWhiteSpace(_branchName)
@@ -264,6 +330,7 @@
     {
         PendingChangesService.OnPendingChangesChanged += LoadChanges;
         AuthService.OnCredentialsChanged += OnCredentialsChanged;
+        Registry.OnActiveProviderChanged += OnCredentialsChanged;
     }
 
     private void OnCredentialsChanged() => InvokeAsync(StateHasChanged);
@@ -396,6 +463,41 @@
         }
     }
 
+    // Non-PR providers (e.g. FTP): upload the tracked changes directly via the active provider.
+    // NOTE: FTP change-set tracking is not yet wired (see concern in the report); _uploadChanges
+    // is empty today, so this path is reached only once tracking is implemented.
+    private async Task UploadChanges()
+    {
+        if (_uploadChanges.Count == 0) return;
+
+        _isCreating = true;
+        StateHasChanged();
+
+        try
+        {
+            var writeResult = await StorageSubmit.SubmitAsync(_uploadChanges, CommitContext.Empty);
+            if (writeResult.Success)
+            {
+                Toast.ShowSuccess($"Uploaded {writeResult.FileResults.Count} file(s) successfully.");
+                _uploadChanges = new();
+                await Close();
+            }
+            else
+            {
+                Toast.ShowError(writeResult.Message ?? "One or more files failed to upload.");
+            }
+        }
+        catch (Exception ex)
+        {
+            Toast.ShowError($"Upload failed: {ex.Message}");
+        }
+        finally
+        {
+            _isCreating = false;
+            StateHasChanged();
+        }
+    }
+
     private void ResetDialog()
     {
         _result = null;
@@ -470,5 +572,6 @@
     {
         PendingChangesService.OnPendingChangesChanged -= LoadChanges;
         AuthService.OnCredentialsChanged -= OnCredentialsChanged;
+        Registry.OnActiveProviderChanged -= OnCredentialsChanged;
     }
 }