Mark the session on screen as Current in the session lists

- The conversation page tells the rail and the sessions modal which
  session it shows (announceShownSession, useShownSession); they reload,
  so a session reopened by ?session_id= shows at once.
- Only that session is Current and greyed out (the active one without
  ?session_id=); the active row then leads back to it.
- The rail lists the session on screen even when it's older than its
  latest sessions.

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

src/layouts/bots/(partials)/rail-bot-session-row.tsx

@@ -9,40 +9,48 @@ type Props = {
     loading?: boolean;
     disabled?: boolean;
     onOpen: () => void;
+    /**
+     * The session the page shows (`?session_id=`, else the active one):
+     * marked Current and greyed out.
+     */
+    current: boolean;
 };
 
 /**
  * One session in the rail's sub-list under the open bot: aligned with the
- * bot's name, its title and how recent. The active one says so; any other
- * reopens on click.
+ * bot's name, its title and how recent. The one on screen is
+ * Current (greyed out); any other opens on click (reopening a closed one,
+ * going back to the active one).
  */
 export default function RailBotSessionRow({
     session,
     loading,
     disabled,
     onOpen,
+    current,
 }: Props) {
-    const active = session.status == "active";
     const at = session.last_activity_at || session.created_at;
 
     return (
         <Button
             title={
-                active
-                    ? "This is the current session"
-                    : `Reopen "${session.title || "Untitled"}"`
+                current
+                    ? "This is the session on screen"
+                    : session.status == "active"
+                      ? "Go back to the active session"
+                      : `Reopen "${session.title || "Untitled"}"`
             }
             type="button"
             variant="ghost"
             color="text"
             loading={loading}
-            disabled={active || disabled}
+            disabled={current || disabled}
             onClick={onOpen}
             buttonContentProps={{ className: "w-full min-w-0 flex-nowrap" }}
             className={twMerge(
                 "w-full h-8 shrink-0 justify-start! items-center! gap-2! rounded-default px-2! @rail:pl-14! text-left text-ink dark:text-ink hover:bg-ink/5 hover:dark:bg-ink/5 focus-visible:ring-2 focus-visible:ring-ink",
-                active &&
-                    "bg-transparent hover:bg-transparent hover:dark:bg-transparent opacity-100!",
+                    current &&
+                        "bg-transparent hover:bg-transparent hover:dark:bg-transparent opacity-100!",
             )}
             loadingProps={{
                 size: "smaller",
@@ -51,18 +59,18 @@ export default function RailBotSessionRow({
             <Span
                 className={twMerge(
                     "grow min-w-0 truncate text-xs leading-4 font-bold",
-                    active ? "text-ink-secondary" : "text-ink",
+                    current ? "text-ink-secondary" : "text-ink",
                 )}
             >
                 {session.title || "Untitled session"}
             </Span>
-            {session.unread && !active ? (
+            {session.unread && !current ? (
                 <Span className="shrink-0 text-[11px] font-bold leading-4 text-ink">
                     New
                 </Span>
             ) : null}
             <Span className="shrink-0 text-[11px] leading-4 text-ink-secondary">
-                {active
+                {current
                     ? "Current"
                     : at
                       ? relativeTime({ at: Number(at) })