kv-wasm: onboarding (setup codes, enrollment tickets, scan-to-join) for the web vault

Mirrors kv-ffi's docs/10 §5 API in WebCore and binds it under the names the web app codes
against: setupPayloadForKit, addDevicePayload, revokeEnrollmentTicket, loginWithSetup,
joinStart/joinPoll/joinCancel, joinApprove, joinSend, and the free function parseSetupPayload
(also callable through the worker client).

Unlike kv-ffi, the Secret Key is not persisted: every unlock on the web takes it, so it is
kept zeroized in the unlocked state and dropped on lock. loginWithSetup refuses a code for a
different server than the configured origin (the browser only talks to its own origin).

Tests: ticket enrollment and scan-to-join in both roles against kv-ffi via the kv-sync test
server, a swapped-approver rejection, a Chrome test (IndexedDB never holds the Secret Key,
JS shapes, error codes) and a Node smoke check of the built package.

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

crates/kv-wasm/src/dto.rs

@@ -181,3 +181,81 @@ pub struct ImportReport {
     pub warnings: Vec<String>,
     pub item_ids: Vec<String>,
 }
+
+// ---------------------------------------------------------------- onboarding (docs/10)
+
+/// A parsed, validated setup payload: everything a new device needs except the master password.
+#[derive(Clone, PartialEq, Eq, Serialize, Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub struct SetupInfo {
+    /// Normalized server URL.
+    pub server_url: String,
+    /// Standard base64 SPKI pins, the format `configure_server` takes. Empty = WebPKI only.
+    #[serde(default)]
+    pub spki_pins: Vec<String>,
+    pub account_id: String,
+    /// Display form `K1-…`.
+    pub secret_key: String,
+    /// Enrollment ticket; `login_with_setup` presents it so no manual approval is needed.
+    #[serde(default)]
+    pub ticket: Option<String>,
+}
+
+impl zeroize::Zeroize for SetupInfo {
+    fn zeroize(&mut self) {
+        self.secret_key.zeroize();
+        self.ticket.zeroize();
+    }
+}
+
+impl std::fmt::Debug for SetupInfo {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.debug_struct("SetupInfo")
+            .field("server_url", &self.server_url)
+            .field("spki_pins", &self.spki_pins)
+            .field("account_id", &self.account_id)
+            .field("secret_key", &"<redacted>")
+            .field("ticket", &self.ticket.as_ref().map(|_| "<redacted>"))
+            .finish()
+    }
+}
+
+/// The "Add a device" QR: a setup payload with a fresh, unbound ticket.
+#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub struct AddDevicePayload {
+    pub payload: String,
+    /// For `revoke_enrollment_ticket` when the user cancels.
+    pub ticket_id: String,
+    /// Unix seconds; hide the QR after this.
+    pub expires_at: i64,
+}
+
+/// Shown by the joining device: a QR for a signed-in phone to scan.
+#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub struct JoinSession {
+    pub qr: String,
+    /// Unix seconds.
+    pub expires_at: i64,
+}
+
+/// Result of `join_poll`: `code` once a phone has scanned the QR, `setup` once it sent the bundle.
+#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub struct JoinProgress {
+    pub code: Option<String>,
+    pub setup: Option<SetupInfo>,
+}
+
+/// Shown by the approving device after scanning: the code to compare and who is asking.
+#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub struct JoinConfirm {
+    /// `"123 456"`. The joining device shows the same code.
+    pub code: String,
+    pub device_name: String,
+    pub platform: PlatformDto,
+    /// Same format as `DeviceDto.key_fingerprint`.
+    pub key_fingerprint: String,
+}