fix: replace IndexedDB with Origin Private File System (OPFS)

OPFS (navigator.storage.getDirectory) provides direct filesystem
access scoped to the app's origin. Much more reliable than IndexedDB
for large blob storage — no transaction blocking, no connection issues.

Layout: recordings/{id}.frames (packed binary) + index.json (metadata)
Each recording stored as a single file write then close.

dist/index.html

@@ -5,7 +5,7 @@
     <link rel="icon" href="/favicon.ico">
     <meta name="viewport" content="width=device-width, initial-scale=1.0">
     <title>MJPEG Stream Viewer</title>
-    <script type="module" crossorigin src="/assets/index-B6qcBY8r.js"></script>
+    <script type="module" crossorigin src="/assets/index-2XEhnc0l.js"></script>
     <link rel="stylesheet" crossorigin href="/assets/index-BTgh_FTp.css">
   </head>
   <body>

src/composables/useStorage.ts

@@ -1,10 +1,15 @@
 /**
- * IndexedDB wrapper — singleton connection, never closed during app lifetime.
+ * Storage layer for MJPEG recordings.
  *
- * All frames packed into a single Blob per recording to avoid
- * multi-blob transaction issues.
+ * Uses Origin Private File System (OPFS) for reliable large-blob storage,
+ * with metadata stored alongside as a JSON index.
  *
- * Binary format inside `data`:
+ * Directory layout under OPFS root:
+ *   recordings/
+ *     index.json          — array of RecordingMeta
+ *     {id}.frames         — packed binary blob (all frames)
+ *
+ * Binary format inside `{id}.frames`:
  *   [4B BE uint32 frameCount]
  *   Per frame: [4B BE uint32 timestamp] [4B BE uint32 jpegLen] [JPEG bytes]
  */
@@ -14,62 +19,52 @@ export interface Frame {
   blob: Blob
 }
 
+export interface RecordingMeta {
+  id: string
+  name: string
+  createdAt: string // ISO
+  duration: number
+  frameCount: number
+  dataSize: number
+}
+
 export interface Recording {
   id: string
   name: string
   createdAt: Date
   duration: number
   frameCount: number
+  /** Blob reference — lazy-loaded from OPFS */
   data: Blob
 }
 
-const DB_NAME = 'mjpeg-viewer'
-const DB_VERSION = 2
-const STORE_NAME = 'recordings'
+const DIR = 'recordings'
+const INDEX_FILE = 'index.json'
 
-// ---- Singleton connection ----
-let db: IDBDatabase | null = null
-let dbPromise: Promise<IDBDatabase> | null = null
+// ---- OPFS helpers ----
 
-function getDB(): Promise<IDBDatabase> {
-  if (db) return Promise.resolve(db)
-  if (dbPromise) return dbPromise
-
-  dbPromise = new Promise((resolve, reject) => {
-    const request = indexedDB.open(DB_NAME, DB_VERSION)
-
-    request.onupgradeneeded = () => {
-      const d = request.result
-      if (d.objectStoreNames.contains(STORE_NAME)) {
-        d.deleteObjectStore(STORE_NAME)
-      }
-      d.createObjectStore(STORE_NAME, { keyPath: 'id' })
+async function getDir(): Promise<FileSystemDirectoryHandle> {
+  const root = await navigator.storage.getDirectory()
+  return root.getDirectoryHandle(DIR, { create: true })
 }
 
-    request.onsuccess = () => {
-      db = request.result
-      // If connection is lost (browser closes it), reset
-      db.onclose = () => {
-        db = null
-        dbPromise = null
+async function readIndex(dir: FileSystemDirectoryHandle): Promise<RecordingMeta[]> {
+  try {
+    const fh = await dir.getFileHandle(INDEX_FILE)
+    const file = await fh.getFile()
+    const text = await file.text()
+    return JSON.parse(text)
+  } catch {
+    // index doesn't exist yet
+    return []
   }
-      resolve(db)
 }
 
-    request.onerror = () => {
-      dbPromise = null
-      reject(request.error)
-    }
-
-    request.onblocked = () => {
-      // A previous connection is still open — this shouldn't happen
-      // with singleton pattern, but if it does, reject to trigger retry
-      dbPromise = null
-      reject(new Error('Database blocked by another connection'))
-    }
-  })
-
-  return dbPromise
+async function writeIndex(dir: FileSystemDirectoryHandle, index: RecordingMeta[]): Promise<void> {
+  const fh = await dir.getFileHandle(INDEX_FILE, { create: true })
+  const writable = await fh.createWritable()
+  await writable.write(JSON.stringify(index))
+  await writable.close()
 }
 
 // ---- Binary pack / unpack ----
@@ -114,45 +109,63 @@ export async function unpackFrames(data: Blob): Promise<Frame[]> {
 // ---- CRUD ----
 
 export async function saveRecording(recording: Recording): Promise<void> {
-  const d = await getDB()
-  return new Promise((resolve, reject) => {
-    const tx = d.transaction(STORE_NAME, 'readwrite')
-    const store = tx.objectStore(STORE_NAME)
-    store.put({
-      ...recording,
+  const dir = await getDir()
+
+  // Write frame data blob
+  const dataFh = await dir.getFileHandle(`${recording.id}.frames`, { create: true })
+  const writable = await dataFh.createWritable()
+  await writable.write(recording.data)
+  await writable.close()
+
+  // Update index
+  const index = await readIndex(dir)
+  index.unshift({
+    id: recording.id,
+    name: recording.name,
     createdAt: recording.createdAt.toISOString(),
+    duration: recording.duration,
+    frameCount: recording.frameCount,
+    dataSize: recording.data.size,
   })
-    tx.oncomplete = () => resolve()
-    tx.onerror = () => reject(tx.error)
-    tx.onabort = () => reject(new Error('Transaction aborted'))
-  })
+  await writeIndex(dir, index)
 }
 
 export async function getAllRecordings(): Promise<Recording[]> {
-  const d = await getDB()
-  return new Promise((resolve, reject) => {
-    const tx = d.transaction(STORE_NAME, 'readonly')
-    const store = tx.objectStore(STORE_NAME)
-    const request = store.getAll()
-    request.onsuccess = () => {
-      const results = (request.result || []).map((r: any) => ({
-        ...r,
-        createdAt: new Date(r.createdAt),
-      }))
-      results.sort((a, b) => b.createdAt.getTime() - a.createdAt.getTime())
-      resolve(results)
-    }
-    request.onerror = () => reject(request.error)
+  const dir = await getDir()
+  const index = await readIndex(dir)
+
+  // Load data blob for each recording
+  const results: Recording[] = []
+  for (const meta of index) {
+    try {
+      const fh = await dir.getFileHandle(`${meta.id}.frames`)
+      const file = await fh.getFile()
+      results.push({
+        id: meta.id,
+        name: meta.name,
+        createdAt: new Date(meta.createdAt),
+        duration: meta.duration,
+        frameCount: meta.frameCount,
+        data: file,
       })
+    } catch {
+      // Orphaned index entry — skip
+    }
+  }
+  return results
 }
 
 export async function deleteRecording(id: string): Promise<void> {
-  const d = await getDB()
-  return new Promise((resolve, reject) => {
-    const tx = d.transaction(STORE_NAME, 'readwrite')
-    const store = tx.objectStore(STORE_NAME)
-    store.delete(id)
-    tx.oncomplete = () => resolve()
-    tx.onerror = () => reject(tx.error)
-  })
+  const dir = await getDir()
+
+  // Delete frame data
+  try {
+    await dir.removeEntry(`${id}.frames`)
+  } catch {
+    // file already gone
+  }
+
+  // Update index
+  const index = await readIndex(dir)
+  await writeIndex(dir, index.filter((m) => m.id !== id))
 }