feat(cloud-files): Explorer-Sidebar-Integration fuer Windows

Registriert den Sync-Ordner als Shell-Namespace-Extension unter
HKEY_CURRENT_USER (kein Admin noetig), sodass er mit eigenem Icon
in der linken Leiste des Datei-Explorers erscheint - wie bei
OneDrive oder Dropbox.

- Neues Modul cloud_files::shell_integration mit install/uninstall
- Registry-Eintraege unter HKCU\Software\Classes\CLSID\{GUID} und
  HKCU\...\Explorer\Desktop\NameSpace\{GUID}
- Nutzt die laufende .exe als Icon-Quelle (fallback: imageres.dll)
- SHChangeNotify(SHCNE_ASSOCCHANGED) damit Explorer sofort aktualisiert
- install/uninstall werden aus register_sync_root/unregister aufgerufen
- winreg-Crate fuer sauberen Registry-Zugriff

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

clients/desktop/src-tauri/Cargo.toml

@@ -42,8 +42,10 @@ windows = { version = "0.58", features = [
     "Win32_System_CorrelationVector",  # gate fuer CF_CALLBACK_INFO / CfExecute / CfConnectSyncRoot
     "Win32_UI_Shell",
     "Win32_Security",
+    "Win32_System_Registry",
 ] }
 widestring = "1"
+winreg = "0.52"
 
 # Linux: FUSE-basiertes Virtual-Filesystem (optional, cargo build --features linux_fuse)
 [target.'cfg(target_os = "linux")'.dependencies]

clients/desktop/src-tauri/src/cloud_files/mod.rs

@@ -43,6 +43,8 @@ pub enum SyncState {
 
 #[cfg(windows)]
 pub mod windows;
+#[cfg(windows)]
+pub mod shell_integration;
 #[cfg(all(target_os = "linux", feature = "linux_fuse"))]
 pub mod linux;
 pub mod sync_loop;

clients/desktop/src-tauri/src/cloud_files/shell_integration.rs

@@ -0,0 +1,143 @@
+//! Explorer-Sidebar-Integration fuer Windows (ohne Admin-Rechte).
+//!
+//! Registriert den Sync-Ordner als Shell-Namespace-Extension unter
+//! HKEY_CURRENT_USER, sodass er mit eigenem Icon in der Navigation
+//! des Datei-Explorers erscheint (wie OneDrive/Dropbox).
+//!
+//! Anders als die eigentliche Cloud Files API ist das reine Registry-
+//! Kosmetik - der Ordner funktioniert auch ohne Sidebar-Eintrag,
+//! nur sieht man ihn dann nicht in der linken Leiste.
+
+#![cfg(windows)]
+
+use std::path::Path;
+use winreg::enums::*;
+use winreg::RegKey;
+
+// Stabile GUID fuer Mini-Cloud - gleiche wie in windows.rs als ProviderId.
+const CLSID_GUID: &str = "{4D696E69-436C-6F75-6444-7566667944AB}";
+
+// Standard-CLSID fuer "Generic Shell Folder Implementation".
+const SHELL_FOLDER_CLSID: &str = "{0E5AAE11-A475-4c5b-AB00-C66DE400274E}";
+
+/// Registriere den Mount-Ordner in der Explorer-Navigation.
+/// `icon_source`: Pfad zu ICO oder EXE mit Icon-Index (z.B. "C:\\app.exe,0")
+pub fn install(
+    display_name: &str,
+    mount_point: &Path,
+    icon_source: &str,
+) -> Result<(), String> {
+    let hkcu = RegKey::predef(HKEY_CURRENT_USER);
+
+    // 1) CLSID-Eintrag unter Software\Classes\CLSID\{GUID}
+    let clsid_path = format!("Software\\Classes\\CLSID\\{}", CLSID_GUID);
+    let (clsid, _) = hkcu
+        .create_subkey(&clsid_path)
+        .map_err(|e| format!("create CLSID: {e}"))?;
+    clsid
+        .set_value("", &display_name.to_string())
+        .map_err(|e| format!("set displayname: {e}"))?;
+    clsid
+        .set_value("System.IsPinnedToNameSpaceTree", &1u32)
+        .map_err(|e| format!("set pinned: {e}"))?;
+    clsid
+        .set_value("SortOrderIndex", &0x42u32)
+        .map_err(|e| format!("set sortorder: {e}"))?;
+
+    // 2) DefaultIcon
+    let (icon_key, _) = clsid
+        .create_subkey("DefaultIcon")
+        .map_err(|e| format!("create DefaultIcon: {e}"))?;
+    icon_key
+        .set_value("", &icon_source.to_string())
+        .map_err(|e| format!("set icon: {e}"))?;
+
+    // 3) InProcServer32 -> shell32.dll (Standard Shell-Folder-Host)
+    let (inproc, _) = clsid
+        .create_subkey("InProcServer32")
+        .map_err(|e| format!("create InProcServer32: {e}"))?;
+    inproc
+        .set_value("", &"%SystemRoot%\\system32\\shell32.dll".to_string())
+        .map_err(|e| format!("set shell32: {e}"))?;
+    inproc
+        .set_value("ThreadingModel", &"Both".to_string())
+        .map_err(|e| format!("set threading: {e}"))?;
+
+    // 4) Instance -> zeigt auf generischen Shell-Folder
+    let (instance, _) = clsid
+        .create_subkey("Instance")
+        .map_err(|e| format!("create Instance: {e}"))?;
+    instance
+        .set_value("CLSID", &SHELL_FOLDER_CLSID.to_string())
+        .map_err(|e| format!("set inst clsid: {e}"))?;
+
+    let (pb, _) = instance
+        .create_subkey("InitPropertyBag")
+        .map_err(|e| format!("create InitPropertyBag: {e}"))?;
+    pb.set_value("Attributes", &0x11u32)
+        .map_err(|e| format!("set attrs pb: {e}"))?;
+    pb.set_value(
+        "TargetFolderPath",
+        &mount_point.to_string_lossy().into_owned(),
+    )
+    .map_err(|e| format!("set target: {e}"))?;
+
+    // 5) ShellFolder-Flags
+    let (sf, _) = clsid
+        .create_subkey("ShellFolder")
+        .map_err(|e| format!("create ShellFolder: {e}"))?;
+    sf.set_value("FolderValueFlags", &0x28u32)
+        .map_err(|e| format!("set folderflags: {e}"))?;
+    sf.set_value("Attributes", &0xF080004Du32)
+        .map_err(|e| format!("set attrs sf: {e}"))?;
+
+    // 6) In die Navigation einhaengen
+    let ns_path = format!(
+        "Software\\Microsoft\\Windows\\CurrentVersion\\Explorer\\Desktop\\NameSpace\\{}",
+        CLSID_GUID
+    );
+    let (ns, _) = hkcu
+        .create_subkey(&ns_path)
+        .map_err(|e| format!("create NameSpace: {e}"))?;
+    ns.set_value("", &display_name.to_string())
+        .map_err(|e| format!("set ns name: {e}"))?;
+
+    // 7) Explorer informieren (SHChangeNotify)
+    notify_shell();
+
+    Ok(())
+}
+
+/// Entferne die Shell-Integration wieder.
+pub fn uninstall() -> Result<(), String> {
+    let hkcu = RegKey::predef(HKEY_CURRENT_USER);
+
+    let ns_path = format!(
+        "Software\\Microsoft\\Windows\\CurrentVersion\\Explorer\\Desktop\\NameSpace\\{}",
+        CLSID_GUID
+    );
+    let _ = hkcu.delete_subkey_all(&ns_path);
+
+    let clsid_path = format!("Software\\Classes\\CLSID\\{}", CLSID_GUID);
+    let _ = hkcu.delete_subkey_all(&clsid_path);
+
+    notify_shell();
+    Ok(())
+}
+
+/// Teilt Explorer mit, dass sich die Shell-Namespace-Liste geaendert hat.
+/// Ohne das sieht man den neuen Eintrag erst nach Explorer-Neustart.
+fn notify_shell() {
+    use windows::Win32::UI::Shell::{SHChangeNotify, SHCNE_ASSOCCHANGED, SHCNF_IDLIST};
+    unsafe {
+        SHChangeNotify(SHCNE_ASSOCCHANGED, SHCNF_IDLIST, None, None);
+    }
+}
+
+/// Standard-Icon-Quelle: die laufende .exe mit Index 0.
+pub fn default_icon_source() -> String {
+    std::env::current_exe()
+        .ok()
+        .and_then(|p| p.to_str().map(|s| format!("{},0", s)))
+        .unwrap_or_else(|| "%SystemRoot%\\system32\\imageres.dll,2".to_string())
+}

clients/desktop/src-tauri/src/cloud_files/windows.rs

@@ -136,11 +136,22 @@ pub fn register_sync_root(
     log_msg(mount_point, "CfRegisterSyncRoot OK");
     connect_callbacks(mount_point)?;
     log_msg(mount_point, "callbacks connected");
+
+    // Explorer-Sidebar-Eintrag mit Wolken-Icon
+    let icon = super::shell_integration::default_icon_source();
+    match super::shell_integration::install(provider_name, mount_point, &icon) {
+        Ok(()) => log_msg(mount_point, "shell integration installed"),
+        Err(e) => log_err(mount_point, &format!("shell integration FAILED: {e}")),
+    }
+
     Ok(())
 }
 
 pub fn unregister_sync_root(mount_point: &PathBuf) -> Result<(), String> {
-    disconnect_callbacks()?;
+    // Shell-Eintrag zuerst entfernen (schlaegt nie fehl).
+    let _ = super::shell_integration::uninstall();
+
+    let _ = disconnect_callbacks();
     let path_wide = U16CString::from_str(mount_point.to_string_lossy().as_ref())
         .map_err(|e| e.to_string())?;
     unsafe {