Persist agent chat sessions and protect manual titles

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

tests/routes/chatSession.test.ts

@@ -0,0 +1,38 @@
+import { describe, expect, it } from "bun:test";
+
+import { shouldGenerateSessionTitle } from "../../src/routes/chatSession.js";
+
+describe("shouldGenerateSessionTitle", () => {
+  it("allows auto-title generation for the first turn when the title was not edited", () => {
+    expect(
+      shouldGenerateSessionTitle({
+        recentTurnCount: 0,
+        isTitleManuallyEdited: false,
+      }),
+    ).toBe(true);
+  });
+
+  it("blocks auto-title generation after the user edits the title manually", () => {
+    expect(
+      shouldGenerateSessionTitle({
+        recentTurnCount: 0,
+        isTitleManuallyEdited: true,
+      }),
+    ).toBe(false);
+  });
+
+  it("only allows auto-title generation during the first two turns", () => {
+    expect(
+      shouldGenerateSessionTitle({
+        recentTurnCount: 1,
+        isTitleManuallyEdited: false,
+      }),
+    ).toBe(true);
+    expect(
+      shouldGenerateSessionTitle({
+        recentTurnCount: 2,
+        isTitleManuallyEdited: false,
+      }),
+    ).toBe(false);
+  });
+});