Removed devices: DeviceRevoked, identity reset and one retry with the ticket

kv-sync: SyncError::DeviceRevoked for 403 device_revoked (drops the session);
the test server answers it after OPAQUE (before the ticket) and for valid
signatures by a revoked device's key.

kv-ffi: CoreError::DeviceRevoked; the foreign DeviceSigner gains reset() (new key
and id). On device_revoked the core resets the identity, forgets the session
and the kept OPAQUE input (no silent re-enrolment) and keeps the vault data; a
login carrying a ticket retries once as the new device. reset_device_identity()
runs the reset on demand. Signed calls (sync, devices, tickets, join) reset too.

kv-wasm: DeviceRevoked; the browser binding replaces the WebCrypto key and id in
IndexedDB (same name and platform), loginWithSetup retries once with a ticket;
resetDeviceIdentity().

Tests: end to end revoked -> reset -> re-enrol with the same ticket (kv-ffi and
web core), no-ticket path, in-browser IndexedDB reset.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

crates/kv-wasm/README.md

@@ -80,7 +80,7 @@ parseSetupPayload(s): SetupInfo;                                // {serverUrl, s
 
 Errors reject with an `Error` whose `name` is `"CoreError"` and whose `code` is one of kv-ffi's
 `CoreError` cases (`Locked`, `NoAccount`, `BadCredentials`, `Invalid`, `NotFound`, `Internal`,
-`NotConfigured`, `NotAuthenticated`, `PendingApproval`, `Network`, `Server` + `status`,
+`NotConfigured`, `NotAuthenticated`, `PendingApproval`, `DeviceRevoked`, `Network`, `Server` + `status`,
 `IntegrityAlarm` + `vaultId`/`reason`), plus `Busy` (a sync is already running) and, from the worker
 client, `InUse` (another tab has the vault open).
 
@@ -125,14 +125,22 @@ two replicas overwriting each other.
    `NotAuthenticated` (ask for the password and `login` again), `PendingApproval`,
    `IntegrityAlarm` (stop and alert: the server rolled back or tampered with a vault) and
    `restoredItemIds` (tell the user an edit brought a deleted item back).
-7. **Storage.** Call `navigator.storage.persist()`. If the browser evicts IndexedDB, unsynced edits
+7. **Removed browser** (kestrove-spec docs/03 "Removed devices"). `DeviceRevoked` from any call means
+   the server removed this browser's device id for good. The vault has already replaced the WebCrypto
+   key and device id in IndexedDB (`deviceId()` changes), dropped the session and kept the local data.
+   `loginWithSetup` with a ticket retries once by itself as the new device and normally resolves `"ok"`.
+   Otherwise show "This device was removed from your account. Set it up again." and the sign-in: the
+   next `login` enrols the new identity (`"pendingApproval"`). `resetDeviceIdentity()` does the same
+   reset on demand. When the user removes a device, warn "To add it back later, set it up again as a new
+   device."
+8. **Storage.** Call `navigator.storage.persist()`. If the browser evicts IndexedDB, unsynced edits
    and the device key are lost and the browser must be approved again.
-8. **Sign out of this browser:** `logout()` (ends the server session), then `wipe()` (removes the
+9. **Sign out of this browser:** `logout()` (ends the server session), then `wipe()` (removes the
    replica and device key; the next login is a new device).
-9. **Import/export:** pass `new Uint8Array(await file.arrayBuffer())`; `exportEncrypted` resolves with
+10. **Import/export:** pass `new Uint8Array(await file.arrayBuffer())`; `exportEncrypted` resolves with
    the `.kvex` bytes for a `Blob` download.
-10. `itemsForUrl` / `matchUrl` match the same host only (no Public Suffix List in this build).
-11. **Onboarding** (docs/10). Same flows and names as kv-ffi; `expiresAt` is Unix **seconds**
+11. `itemsForUrl` / `matchUrl` match the same host only (no Public Suffix List in this build).
+12. **Onboarding** (docs/10). Same flows and names as kv-ffi; `expiresAt` is Unix **seconds**
     and codes look like `"123 456"`, as in kv-ffi.
     * *Sign in with a setup code*: `parseSetupPayload(text)` (scanned or pasted; it is a secret,
       so never put it in a URL or register `kestrove://` as a handler), then