fix: per-entry AES-GCM key isolation — HKDF info = entryId + 'sync-entry-v1' instead of shared salt (v3.6.97)

@@ -50,7 +50,9 @@5050   SignedDeviceManifest,5151 } from "../shared/sync-types";5252 53-const ENTRY_KEY_SALT = new TextEncoder().encode("peach-sync-entry-v1");53+// Each entry uses a unique AES-GCM key: HKDF(masterKey, info = entryId + "sync-entry-v1").54+// The info binding prevents a ciphertext from one entry slot being replayed into another.55+const ENTRY_KEY_INFO_SUFFIX = "sync-entry-v1";5456 const ENTRY_AAD = "peach-sync-entry-v1";5557 5658 export class VaultLockedError extends Error {@@ -109,12 +111,12 @@109111     async getEncryptedEntries(entryIds) {110112       requireUnlocked();111113       const masterKey = requireMasterKey();112-      const entryKey = await deriveEntryKey(masterKey);113114       const out: Record<string, string> = {};114115       for (const id of entryIds) {115116         const entry = getEntryById(id);116117         if (!entry) continue;117-        out[id] = await encryptEntry(entryKey, entry);118+        const key = await deriveEntryKey(masterKey, id);119+        out[id] = await encryptEntry(key, entry);118120       }119121       return out;120122     },@@ -122,10 +124,10 @@122124     async applyEntries(entries) {123125       requireUnlocked();124126       const masterKey = requireMasterKey();125-      const entryKey = await deriveEntryKey(masterKey);126127       const decrypted: VaultEntry[] = [];127128       for (const [id, envelope] of Object.entries(entries)) {128-        const entry = await decryptEntryOrNull(entryKey, envelope);129+        const key = await deriveEntryKey(masterKey, id);130+        const entry = await decryptEntryOrNull(key, envelope);129131         if (!entry) continue;130132         // The map key is the authority on id — refuse mismatched envelopes131133         // so a swapped envelope can't poison a different entry slot.@@ -254,8 +256,9 @@254256   return hexToBytes(hex);255257 }256258 257-async function deriveEntryKey(masterKey: Uint8Array): Promise<CryptoKey> {258-  const raw = new HKDF(SHA256, masterKey, ENTRY_KEY_SALT, new Uint8Array(0)).expand(32);259+async function deriveEntryKey(masterKey: Uint8Array, entryId: string): Promise<CryptoKey> {260+  const info = new TextEncoder().encode(entryId + ENTRY_KEY_INFO_SUFFIX);261+  const raw = new HKDF(SHA256, masterKey, new Uint8Array(0), info).expand(32);259262   return crypto.subtle.importKey(260263     "raw",261264     raw.buffer as ArrayBuffer,