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/pages/admin/bots/[bot_id]/(utils)/sync-session-query.ts

@@ -0,0 +1,25 @@
+import type { BUN_SQLITE_COBBLE_BOT_SESSIONS } from "@/db/types/db";
+
+type Params = {
+    session: Pick<BUN_SQLITE_COBBLE_BOT_SESSIONS, "id" | "status">;
+};
+
+/**
+ * Keeps the address on the session the thread shows: `?session_id=` for a
+ * closed one, a plain address for the active one (or when the asked one
+ * couldn't be shown). Replaces the entry, so the back button isn't
+ * filled with it.
+ */
+export default function syncSessionQuery({ session }: Params) {
+    const url = new URL(window.location.href);
+
+    if (session.status == "active" || !session.id) {
+        url.searchParams.delete("session_id");
+    } else {
+        url.searchParams.set("session_id", String(session.id));
+    }
+
+    if (url.href != window.location.href) {
+        window.history.replaceState(window.history.state, "", url.href);
+    }
+}