feat(tui): unify session history and context

tui/src/session-state.test.ts

@@ -0,0 +1,27 @@
+import { afterEach, describe, expect, test } from "bun:test"
+import { mkdtemp, readFile, rm } from "node:fs/promises"
+import { tmpdir } from "node:os"
+import { join } from "node:path"
+
+import { rememberChat } from "./session-state"
+
+describe("TUI session state", () => {
+  let directory = ""
+
+  afterEach(async () => {
+    if (directory) await rm(directory, { recursive: true, force: true })
+    directory = ""
+  })
+
+  test("atomically remembers the last attached gateway chat", async () => {
+    directory = await mkdtemp(join(tmpdir(), "nanobot-tui-state-"))
+    const path = join(directory, "nested", "state.json")
+
+    await rememberChat(path, "chat-123")
+
+    expect(JSON.parse(await readFile(path, "utf8"))).toEqual({
+      schema_version: 1,
+      chat_id: "chat-123",
+    })
+  })
+})