Name sessions with the model and keep the rail list live

Sessions no longer take their title from the first message: once the first exchange is sent, the text model writes the title and summary, which the rail and sessions list show. The summary records how many messages it covers so a stale one is rewritten before it is carried into the next session.

The sessions hook now reloads on live message and session events, so a session started by the first message, a rollover or another tab appears without a reload. New sessions are pushed as server:bot-session, both from the process that changed them and through the live relay.

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

@@ -0,0 +1,27 @@
+import { describe, expect, test } from "bun:test";
+import parseSessionName from "./parse-session-name";
+
+describe("parseSessionName", () => {
+    test("reads a title and summary", () => {
+        expect(parseSessionName({ text: `{"title":"Tidy invoices","summary":"- sorted them"}` })).toEqual({
+            title: "Tidy invoices",
+            summary: "- sorted them",
+        });
+    });
+
+    test("tolerates a code fence around the object", () => {
+        expect(
+            parseSessionName({
+                text: "```json\n{\"title\":\"Plans\",\"summary\":\"- a trip\"}\n```",
+            }),
+        ).toEqual({ title: "Plans", summary: "- a trip" });
+    });
+
+    test("is null when either part is missing or the JSON is bad", () => {
+        expect(parseSessionName({})).toBeNull();
+        expect(parseSessionName({ text: "" })).toBeNull();
+        expect(parseSessionName({ text: `{"title":"Only a title"}` })).toBeNull();
+        expect(parseSessionName({ text: `{"title":"","summary":"- a trip"}` })).toBeNull();
+        expect(parseSessionName({ text: "{nope" })).toBeNull();
+    });
+});