refactor(shared): move the web push types into their own file

shared/protocol.ts

@@ -439,10 +439,7 @@ export interface TailscaleAccess {
 
 export type { PortalStatus } from "./portal.ts";
 
-/** GET /api/push: base64url VAPID public key, the `applicationServerKey` a browser subscribes with. */
-export interface PushKey {
-  readonly public_key: string;
-}
+export type { PushKey, PushPayload } from "./push.ts";
 
 /** One turn of a structured agent conversation (the chat lens source). */
 export interface ConversationTurn {
@@ -1019,22 +1016,6 @@ export interface PromptAnswer {
   draft?: { option_indices: number[]; custom_text: string };
 }
 
-/**
- * The JSON inside every web push, decrypted by the device's service worker (public/sw.js)
- * and shown as a notification. `pane_id` is null for the enable-confirmation push; `tag`
- * is shared with the in-tab notification of the same pane, so one replaces the other.
- */
-export interface PushPayload {
-  /** Absent in legacy payloads means local. */
-  machine_id?: string;
-  pane_id: string | null;
-  /** The workspace the pane was last seen in, so the tap of an ended pane opens that workspace. Absent when not known. */
-  workspace_id?: string;
-  title: string;
-  body: string;
-  tag: string;
-}
-
 /** WebSocket at /ws
  *
  *  Client -> server frames: attach {pane_id, cols, rows} | detach {pane_id} | input {pane_id, text}

shared/push.ts

@@ -0,0 +1,20 @@
+/** GET /api/push: base64url VAPID public key, the `applicationServerKey` a browser subscribes with. */
+export interface PushKey {
+  readonly public_key: string;
+}
+
+/**
+ * The JSON inside every web push, decrypted by the device's service worker (public/sw.js)
+ * and shown as a notification. `pane_id` is null for the enable-confirmation push; `tag`
+ * is shared with the in-tab notification of the same pane, so one replaces the other.
+ */
+export interface PushPayload {
+  /** Absent in legacy payloads means local. */
+  machine_id?: string;
+  pane_id: string | null;
+  /** The workspace the pane was last seen in, so the tap of an ended pane opens that workspace. Absent when not known. */
+  workspace_id?: string;
+  title: string;
+  body: string;
+  tag: string;
+}