Add recent folders feature with localStorage persistence

- Create FolderSelectionView component showing recent folders and browse option
- Store up to 10 recent folders in localStorage with timestamps
- Show folder selection view on app start when no instances exist
- Display folder selection modal when creating new instance from existing instance
- Add keyboard navigation (arrows, page up/down, home/end, enter, delete)
- Add ability to remove folders from recent list
- Track folder access time and display relative timestamps
- Close modal with Escape key or close button
- Update preferences store with recent folders management

src/stores/preferences.ts

@@ -1,11 +1,18 @@
 import { createSignal } from "solid-js"
 
 const STORAGE_KEY = "opencode-preferences"
+const RECENT_FOLDERS_KEY = "opencode-recent-folders"
+const MAX_RECENT_FOLDERS = 10
 
 interface Preferences {
   showThinkingBlocks: boolean
 }
 
+interface RecentFolder {
+  path: string
+  lastAccessed: number
+}
+
 const defaultPreferences: Preferences = {
   showThinkingBlocks: false,
 }
@@ -30,7 +37,28 @@ function savePreferences(prefs: Preferences): void {
   }
 }
 
+function loadRecentFolders(): RecentFolder[] {
+  try {
+    const stored = localStorage.getItem(RECENT_FOLDERS_KEY)
+    if (stored) {
+      return JSON.parse(stored)
+    }
+  } catch (error) {
+    console.error("Failed to load recent folders:", error)
+  }
+  return []
+}
+
+function saveRecentFolders(folders: RecentFolder[]): void {
+  try {
+    localStorage.setItem(RECENT_FOLDERS_KEY, JSON.stringify(folders))
+  } catch (error) {
+    console.error("Failed to save recent folders:", error)
+  }
+}
+
 const [preferences, setPreferences] = createSignal<Preferences>(loadPreferences())
+const [recentFolders, setRecentFolders] = createSignal<RecentFolder[]>(loadRecentFolders())
 
 function updatePreferences(updates: Partial<Preferences>): void {
   const updated = { ...preferences(), ...updates }
@@ -42,4 +70,19 @@ function toggleShowThinkingBlocks(): void {
   updatePreferences({ showThinkingBlocks: !preferences().showThinkingBlocks })
 }
 
-export { preferences, updatePreferences, toggleShowThinkingBlocks }
+function addRecentFolder(path: string): void {
+  const folders = recentFolders().filter((f) => f.path !== path)
+  folders.unshift({ path, lastAccessed: Date.now() })
+
+  const trimmed = folders.slice(0, MAX_RECENT_FOLDERS)
+  setRecentFolders(trimmed)
+  saveRecentFolders(trimmed)
+}
+
+function removeRecentFolder(path: string): void {
+  const folders = recentFolders().filter((f) => f.path !== path)
+  setRecentFolders(folders)
+  saveRecentFolders(folders)
+}
+
+export { preferences, updatePreferences, toggleShowThinkingBlocks, recentFolders, addRecentFolder, removeRecentFolder }

src/stores/ui.ts

@@ -3,6 +3,7 @@ import { createSignal } from "solid-js"
 const [hasInstances, setHasInstances] = createSignal(false)
 const [selectedFolder, setSelectedFolder] = createSignal<string | null>(null)
 const [isSelectingFolder, setIsSelectingFolder] = createSignal(false)
+const [showFolderSelection, setShowFolderSelection] = createSignal(false)
 
 const [instanceTabOrder, setInstanceTabOrder] = createSignal<string[]>([])
 const [sessionTabOrder, setSessionTabOrder] = createSignal<Map<string, string[]>>(new Map())
@@ -26,6 +27,8 @@ export {
   setSelectedFolder,
   isSelectingFolder,
   setIsSelectingFolder,
+  showFolderSelection,
+  setShowFolderSelection,
   instanceTabOrder,
   setInstanceTabOrder,
   sessionTabOrder,