fix(tui): restore compaction model marker

packages/schema/src/session-event.ts

@@ -488,6 +488,7 @@ export namespace Compaction {
     schema: {
       ...Base,
       reason: Started.data.fields.reason,
+      model: Model.Ref.pipe(optional),
       text: Schema.String,
       recent: Schema.String,
     },

packages/schema/src/session-message.ts

@@ -222,6 +222,7 @@ export const CompactionCompleted = Schema.Struct({
   ...CompactionBase,
   status: Schema.tag("completed"),
   reason: Schema.Literals(["auto", "manual"]),
+  model: Model.Ref.pipe(optional),
   summary: Schema.String,
   recent: Schema.String,
 }).annotate({ identifier: "Session.Message.Compaction.Completed" })

packages/schema/test/session-message.test.ts

@@ -0,0 +1,21 @@
+import { describe, expect, test } from "bun:test"
+import { Schema } from "effect"
+import { SessionMessage } from "../src/session-message.js"
+
+describe("session message", () => {
+  test("decodes completed compactions recorded before model attribution", () => {
+    const encoded = {
+      type: "compaction" as const,
+      id: "msg_compaction",
+      time: { created: 0 },
+      status: "completed" as const,
+      reason: "manual" as const,
+      summary: "summary",
+      recent: "",
+    }
+    const message = Schema.decodeUnknownSync(SessionMessage.CompactionCompleted)(encoded)
+
+    expect(message.model).toBeUndefined()
+    expect(Schema.encodeSync(SessionMessage.CompactionCompleted)(message)).toEqual(encoded)
+  })
+})