Cloud actions: iCloud Drive only, via FileManager ubiquity APIs

`NSFileProviderManager.evictItemWithIdentifier` etc. failed in
practice with `NSFileProviderErrorProviderNotFound` ("The application
cannot be used right now") — its host-side methods are reserved for
the app that *bundles* the FP extension, not third-party callers
like Cmdr. There's no public path for non-host apps to evict /
download arbitrary File Provider items; Finder uses private XPC.

The `FileManager.evictUbiquitousItem(at:)` /
`startDownloadingUbiquitousItem(at:)` APIs route through iCloud's
separate ubiquity infrastructure and accept any URL inside an
iCloud container. Switching to those works for iCloud Drive paths
and gives synchronous `Result<(), NSError>` (no completion-handler
machinery, no `objc2-file-provider` crate at all).

Effect:
- `Make available offline` / `Remove download` only show in the
  context menu for paths under
  `~/Library/Mobile Documents/com~apple~CloudDocs/`.
- For Dropbox / GoogleDrive / OneDrive / Box files the menu items
  no longer appear — the user has to use the provider's own client
  (or Finder). That's the honest state with public APIs.
- `is_in_cloud_storage` removed (was unused outside the now-deleted
  fallback path); `is_in_icloud_drive` is the strict gate.
- `objc2-file-provider` dropped from `Cargo.toml`. Module-doc
  comment in `cloud_actions.rs` records the dead-end so future
  agents don't re-litigate `NSFileProviderManager`.

Author: vdavid

Cargo.lock

@@ -157,9 +157,6 @@ objc2-app-kit = { version = "0.3", features = [
     "NSApplication", "NSMenu", "NSMenuItem", "NSPasteboard", "NSRunningApplication",
     "NSWorkspace", "NSPanel", "NSOpenPanel", "NSSavePanel", "NSWindow", "NSResponder",
 ] }
-objc2-file-provider = { version = "0.3", features = [
-    "Extension", "NSFileProviderDomain", "NSFileProviderItem", "NSFileProviderError",
-] }
 block2 = "0.6"
 security-framework = "3.2"
 # Drive indexing: macOS FSEvents watcher with event IDs and sinceWhen replay

apps/desktop/src-tauri/Cargo.toml

@@ -74,16 +74,16 @@ pub fn show_file_context_menu<R: Runtime>(
 
 #[cfg(target_os = "macos")]
 fn build_file_context_info(primary_path: &str, all_paths: &[String]) -> FileContextInfo {
-    use crate::file_system::cloud_actions::is_in_cloud_storage;
+    use crate::file_system::cloud_actions::is_in_icloud_drive;
     use crate::file_system::open_with::compute_open_with_choices;
     use crate::file_system::sync_status::get_sync_statuses;
     use std::path::PathBuf;
 
     let path_buf = PathBuf::from(primary_path);
-    let is_cloud = is_in_cloud_storage(&path_buf);
+    let is_icloud_drive = is_in_icloud_drive(&path_buf);
 
     // Sync status of the primary path only — drives the cloud-action label.
-    let sync_status = if is_cloud {
+    let sync_status = if is_icloud_drive {
         let mut statuses = get_sync_statuses(vec![primary_path.to_string()]);
         statuses.remove(primary_path).unwrap_or_default()
     } else {
@@ -94,7 +94,7 @@ fn build_file_context_info(primary_path: &str, all_paths: &[String]) -> FileCont
 
     FileContextInfo {
         sync_status,
-        is_cloud,
+        is_icloud_drive,
         open_with,
     }
 }

apps/desktop/src-tauri/src/commands/ui.rs

@@ -6,12 +6,19 @@ Submodule docs: [listing/](listing/CLAUDE.md), [write_operations/](write_operati
 
 ## Cloud actions and "Open with" (macOS)
 
-- `cloud_actions.rs` — wraps `NSFileProviderManager.evictItem(...)` and
-  `requestDownloadForItem(...)` so the file context menu can offer "Make available offline" and
-  "Remove download" for any File-Provider-managed file (iCloud Drive, Dropbox, Google Drive,
-  OneDrive, Box). Detection is fast (`is_in_cloud_storage` — pure path-prefix check against
-  `~/Library/Mobile Documents/com~apple~CloudDocs` and `~/Library/CloudStorage/`); the actual
-  evict/download chain calls async FP APIs synchronously via completion handlers + `mpsc::sync_channel`.
+- `cloud_actions.rs` — wraps `FileManager.evictUbiquitousItem(at:)` and
+  `startDownloadingUbiquitousItem(at:)` so the file context menu can offer "Make available
+  offline" and "Remove download". **iCloud Drive only.** `NSFileProviderManager`'s host-side
+  methods looked like the cross-provider API but are reserved for the app that *bundles* the
+  File Provider extension (Dropbox.app for Dropbox etc.) — third-party apps get
+  `NSFileProviderErrorProviderNotFound` ("The application cannot be used right now") on the
+  enumerate / evict / download calls. The `FileManager` ubiquity APIs route through iCloud's
+  separate code path and accept any URL inside an iCloud container, so we offer the menu
+  items only for paths under `~/Library/Mobile Documents/com~apple~CloudDocs/`. Module-doc
+  comment in `cloud_actions.rs` has the full story for future agents.
+
+  `is_in_icloud_drive` (strict path-prefix check against
+  `~/Library/Mobile Documents/com~apple~CloudDocs/`) gates the eviction menu items.
 - `open_with.rs` — `URLsForApplicationsToOpenURL:` for candidate apps, with multi-selection
   intersection. Session cache keyed by lowercased extension. Subscribes to
   `NSWorkspace.didLaunchApplicationNotification` / `didTerminateApplicationNotification` for