feat(preload): add file.list, file.pickFolder, file.pickFile convenience methods

src/renderer/components/sidebar/Sidebar.tsx

@@ -1,4 +1,5 @@
-import { ChevronRight } from 'lucide-react';
+import { ChevronRight, FolderOpen } from 'lucide-react';
+import { Button } from '@/components/ui/button';
 import { Collapsible, CollapsibleTrigger, CollapsibleContent } from '@/components/ui/collapsible';
 import { ScrollArea } from '@/components/ui/scroll-area';
 import { useFileStore } from '@/stores/file-store';
@@ -6,7 +7,7 @@ import { FileTree } from './FileTree';
 import { Outline } from './Outline';
 
 export function Sidebar() {
-  const rootPath = useFileStore((s) => s.rootPath);
+  const tree = useFileStore((s) => s.tree);
 
   return (
     <div className="flex h-full flex-col gap-3">
@@ -20,9 +21,12 @@ export function Sidebar() {
         </CollapsibleTrigger>
         <CollapsibleContent>
           <ScrollArea className="h-[calc(100vh-240px)]">
-            {!rootPath ? (
-              <div className="flex flex-col items-center justify-center gap-2 py-8 text-xs text-muted-foreground">
+            {!tree ? (
+              <div className="flex flex-col items-center gap-2 p-4 text-xs text-muted-foreground">
                 <span>No folder opened</span>
+                <Button size="sm" variant="outline" onClick={() => useFileStore.getState().openFolderDialog()}>
+                  <FolderOpen className="mr-1" /> Open Folder
+                </Button>
               </div>
             ) : (
               <FileTree />

src/renderer/lib/ipc.ts

@@ -66,6 +66,10 @@ export const ipc = {
       safeCall('file', 'write', path, content),
     list: (dir: string): Promise<IpcResult<FileEntry[] | ChannelMissing>> =>
       safeCall('file', 'list', dir),
+    pickFolder: (): Promise<IpcResult<string | null | ChannelMissing>> =>
+      safeCall('file', 'pickFolder'),
+    pickFile: (): Promise<IpcResult<string | null | ChannelMissing>> =>
+      safeCall('file', 'pickFile'),
     onChange: (cb: (path: string) => void): (() => void) => {
       if (typeof window === 'undefined' || !window.electronAPI?.file?.onChange) {
         return () => {};

src/renderer/stores/file-store.ts

@@ -39,6 +39,9 @@ interface FileState {
   markTabClean: (id: string) => void;
   markTabDirty: (id: string) => void;
   reorderTabs: (fromIndex: number, toIndex: number) => void;
+  openFolderDialog: () => Promise<void>;
+  openFileDialog: () => Promise<void>;
+  saveActiveBuffer: () => Promise<boolean>;
 }
 
 function entryToNode(entry: FileEntry): FileNode {
@@ -191,5 +194,32 @@ export const useFileStore = create<FileState>()(
         tabs.splice(toIndex, 0, moved);
       });
     },
+
+    openFolderDialog: async () => {
+      const result = await ipc.file.pickFolder();
+      if (!result.ok || result.data === null) return;
+      await useFileStore.getState().openFolder(result.data);
+    },
+
+    openFileDialog: async () => {
+      const result = await ipc.file.pickFile();
+      if (!result.ok || result.data === null) return;
+      await useFileStore.getState().openFile(result.data);
+    },
+
+    saveActiveBuffer: async () => {
+      const { activeTabId } = useFileStore.getState();
+      if (!activeTabId) return false;
+
+      const buffer = useEditorStore.getState().buffers.get(activeTabId);
+      if (!buffer) return false;
+
+      const writeResult = await ipc.file.write(activeTabId, buffer.content);
+      if (!writeResult.ok) return false;
+
+      useEditorStore.getState().markSaved(activeTabId);
+      useFileStore.getState().markTabClean(activeTabId);
+      return true;
+    },
   }))
 );