fix(collections): document context menu targeting + off-main AppKit calls

Sidebar document rows lived inside the collection's single List row —
on macOS, a List row's own context menu wins over any nested
.contextMenu deeper in that row's content, so right-clicking a
document always showed the collection's menu. Swapped List for a
plain ScrollView/LazyVStack (every row already does its own selection
highlighting, so List wasn't buying anything here).

Also pins the new document-action views to @MainActor: Download/Print
call NSSavePanel/NSPrintOperation/NSPasteboard after an await, and
without a fixed actor those functions could resume on a background
executor — off-main AppKit calls, which is what was producing the
ViewBridge/nw_connection console spam.

Outpost/Features/Collections/CollectionDocumentsOutline.swift

@@ -66,6 +66,12 @@ struct CollectionDocumentsOutline: View {
     }
 }
 
+/// `NSSavePanel`/`NSPrintOperation`/`NSPasteboard` in the action functions
+/// below must run on the main thread — without pinning this to `@MainActor`,
+/// a `Task` launched from a menu action can resume on a background executor
+/// after its first `await`, and calling those APIs off-main is what produced
+/// the ViewBridge/`nw_connection` console spam (and worse, silent failures).
+@MainActor
 private struct DocumentNodeRow: View {
     let apiClient: OutlineAPIClient
     let node: DocumentNode

Outpost/Features/Collections/CollectionsTreeView.swift

@@ -65,20 +65,31 @@ struct CollectionsTreeView: View {
                     description: Text("Collections you have access to will appear here.")
                 )
             } else {
-                List {
-                    ForEach(viewModel.collections) { collection in
-                        CollectionTreeRow(
-                            apiClient: viewModel.apiClient,
-                            collection: collection,
-                            isExpanded: expandedCollectionIDs.contains(collection.id),
-                            isSelected: selectedCollection?.id == collection.id,
-                            selectedDocumentID: selectedDocumentID,
-                            onToggle: { toggle(collection) },
-                            onSelectDocument: { chain in onSelectDocument(collection, chain) },
-                            onSearchInCollection: onSearchInCollection,
-                            onCollectionsChanged: { await viewModel.load() }
-                        )
+                // Plain `ScrollView`/`LazyVStack`, not `List`: on macOS, a
+                // `List` row's context menu wins over any `.contextMenu`
+                // nested deeper inside that row's content (right-clicking a
+                // document row inside an expanded `CollectionTreeRow` showed
+                // the collection's menu instead of the document's) — every
+                // row here already does its own selection highlighting, so
+                // `List` wasn't buying anything but that bug.
+                ScrollView {
+                    LazyVStack(alignment: .leading, spacing: 2) {
+                        ForEach(viewModel.collections) { collection in
+                            CollectionTreeRow(
+                                apiClient: viewModel.apiClient,
+                                collection: collection,
+                                isExpanded: expandedCollectionIDs.contains(collection.id),
+                                isSelected: selectedCollection?.id == collection.id,
+                                selectedDocumentID: selectedDocumentID,
+                                onToggle: { toggle(collection) },
+                                onSelectDocument: { chain in onSelectDocument(collection, chain) },
+                                onSearchInCollection: onSearchInCollection,
+                                onCollectionsChanged: { await viewModel.load() }
+                            )
+                        }
                     }
+                    .padding(.horizontal, 8)
+                    .padding(.vertical, 4)
                 }
             }
         }

Outpost/Features/Collections/DocumentHistorySheet.swift

@@ -5,6 +5,7 @@ import OutlineKit
 /// Read-only revision list, backed by `revisions.list`. No diff/restore view —
 /// `revisions.list` omits body content for performance, and restoring is a
 /// bigger follow-up feature, not a one-off action.
+@MainActor
 struct DocumentHistorySheet: View {
     @Environment(\.dismiss) private var dismiss
 

Outpost/Features/Collections/DocumentInsightsSheet.swift

@@ -4,6 +4,7 @@ import OutlineKit
 
 /// Backed by `documents.insights` — server returns an error if insights
 /// aren't enabled on the document, surfaced like any other load failure.
+@MainActor
 struct DocumentInsightsSheet: View {
     @Environment(\.dismiss) private var dismiss
 

Outpost/Features/Collections/DocumentPresentSheet.swift

@@ -6,6 +6,7 @@ import OutlineKit
 /// Distraction-free reading view — no toolbar/sidebar chrome, larger type.
 /// Presentation is just a bigger render of the same markdown, not a real
 /// slide-by-slide deck (Outline's own "Present" isn't slide-based either).
+@MainActor
 struct DocumentPresentSheet: View {
     @Environment(\.dismiss) private var dismiss
 

Outpost/Features/Collections/DocumentSearchSheet.swift

@@ -8,6 +8,7 @@ import OutlineKit
 /// text instead of the styled reader view — the tradeoff is losing rich
 /// rendering in exchange for real match highlighting and scroll-to-match via
 /// `ScrollViewReader`, which wouldn't be possible against an opaque view.
+@MainActor
 struct DocumentSearchSheet: View {
     @Environment(\.dismiss) private var dismiss
 

Outpost/Features/Collections/MoveDocumentSheet.swift

@@ -7,6 +7,7 @@ import OutlineKit
 /// picking a destination deeper than one level (i.e. can't move under a
 /// grandchild) — kept intentionally shallow rather than mirroring the full
 /// sidebar tree in a picker.
+@MainActor
 struct MoveDocumentSheet: View {
     @Environment(\.dismiss) private var dismiss