Carry conversations into new sessions with a visible summary

- Bots get continue_in_new_session: the bot writes a title and summary,
  the session closes for good (read-only) and the new one opens with the
  summary as a "Carried over from the last session" message that links
  back to the old session.
- Continue in new session (conversation menu, sessions modal) and the
  automatic rollover at the session length do the same; New session now
  starts a fresh, unlinked session.
- Session length is an app setting in Settings > General.
- ?session_id= opens a session; a carried-over one shows a bar linking to
  where the conversation went on instead of the composer.
- The thread can open the previous session above the current one (shown
  only, never in the prompt), and replies get search_past_sessions and
  read_past_session.
- Sessions are named from their opening messages, not their latest, and
  a carried summary is labelled as the earlier session's.

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

src/bots-queue/session-name-transcript.test.ts

@@ -0,0 +1,27 @@
+import { describe, expect, test } from "bun:test";
+import sessionNameTranscript from "./session-name-transcript";
+
+describe("sessionNameTranscript", () => {
+    test("reads the exchange as the user's and the bot's", () => {
+        expect(
+            sessionNameTranscript({
+                messages: [
+                    { id: 1, author: "user", text: "Create a bot" },
+                    { id: 2, author: "bot", text: "Done." },
+                ],
+            }),
+        ).toBe("User: Create a bot\n\nYou: Done.");
+    });
+
+    test("marks a carried summary as the earlier session's, not the bot's words", () => {
+        const transcript = sessionNameTranscript({
+            messages: [
+                { id: 1, author: "bot", text: "- Crew set up", carried_from_session_id: 9 },
+                { id: 2, author: "user", text: "Continue here" },
+            ],
+        });
+
+        expect(transcript).toStartWith("(Summary of the earlier session this one carries on from)\n- Crew set up");
+        expect(transcript).not.toContain("You: - Crew set up");
+    });
+});