feat(app): add font cache management hooks

desktop/capabilities/default.json

@@ -23,6 +23,10 @@
       "identifier": "fs:allow-mkdir",
       "allow": [{ "path": "**" }]
     },
+    {
+      "identifier": "fs:allow-remove",
+      "allow": [{ "path": "**" }]
+    },
     {
       "identifier": "fs:allow-watch",
       "allow": [{ "path": "**" }]

src/app/editor/fonts/cache.ts

@@ -14,6 +14,12 @@ type FontCacheManifest = {
   entries: Partial<Record<string, FontCacheEntry>>
 }
 
+export interface DownloadedFontCacheSummary {
+  count: number
+  byteLength: number
+  updatedAt: number | null
+}
+
 const CACHE_DIR = 'font-cache/v1'
 const MANIFEST_PATH = `${CACHE_DIR}/manifest.json`
 const EMPTY_MANIFEST: FontCacheManifest = { version: 1, entries: {} }
@@ -59,6 +65,25 @@ async function writeManifest(manifest: FontCacheManifest) {
   })
 }
 
+export async function downloadedFontCacheSummary(): Promise<DownloadedFontCacheSummary> {
+  const manifest = await readManifest()
+  const entries = Object.values(manifest.entries).filter((entry): entry is FontCacheEntry => !!entry)
+  return {
+    count: entries.length,
+    byteLength: entries.reduce((sum, entry) => sum + entry.byteLength, 0),
+    updatedAt: entries.length > 0 ? Math.max(...entries.map((entry) => entry.updatedAt)) : null
+  }
+}
+
+export async function clearDownloadedFontCache(): Promise<void> {
+  const { BaseDirectory, remove } = await import('@tauri-apps/plugin-fs')
+  try {
+    await remove(CACHE_DIR, { baseDir: BaseDirectory.AppLocalData, recursive: true })
+  } catch (error) {
+    console.warn('Downloaded font cache clear skipped:', error)
+  }
+}
+
 export function createTauriDownloadedFontCache(): DownloadedFontCache {
   return {
     async read(family, style) {

src/app/editor/fonts/index.ts

@@ -1,7 +1,11 @@
 import { IS_TAURI } from '@open-pencil/core/constants'
 import { fontManager, styleToWeight, type LocalFontAccessState } from '@open-pencil/core/text'
 
-import { createTauriDownloadedFontCache } from '@/app/editor/font-cache'
+import {
+  clearDownloadedFontCache as clearTauriDownloadedFontCache,
+  createTauriDownloadedFontCache,
+  downloadedFontCacheSummary as tauriDownloadedFontCacheSummary
+} from '@/app/editor/fonts/cache'
 
 if (typeof navigator !== 'undefined') {
   fontManager.setFallbackUserAgent(navigator.userAgent)
@@ -49,6 +53,20 @@ export async function requestLocalFontAccess(): Promise<string[]> {
   return fontManager.listFamilies()
 }
 
+export async function downloadedFontCacheSummary() {
+  if (!IS_TAURI) return { count: 0, byteLength: 0, updatedAt: null }
+  return tauriDownloadedFontCacheSummary()
+}
+
+export async function clearDownloadedFontCache(): Promise<void> {
+  if (!IS_TAURI) return
+  await clearTauriDownloadedFontCache()
+}
+
+export async function predownloadFallbackFonts() {
+  return fontManager.ensureFallbackPack()
+}
+
 function registerFontFaces(fonts: TauriFontFamily[]): void {
   if (typeof document === 'undefined') return
   for (const { family } of fonts) {