Navbar with AI chats (#18161)

## Summary
Add Home/Chat tabs and a dedicated threads list in the navigation
drawer.

## Changes
- **Navbar tabs:** Tabs in the drawer to switch between Home and Chat
(with “New chat” button). Shown on desktop when expanded and on mobile
below the workspace selector.
- **Navbar threads list:** New `NavigationDrawerAIChatThreadsList` for
the Chat tab with date groups (Today / Yesterday / Older), thread rows
as `NavigationDrawerItem` (IconComment, title, timestamp). Shared
`useAIChatThreadClick` hook used by navbar and command menu; navbar
passes `resetNavigationStack: true`.
- **NavigationDrawerItem:** New `alwaysShowRightOptions` prop so the
timestamp is always visible (no hover-only).

---------

Co-authored-by: Etienne <45695613+etiennejouan@users.noreply.github.com>
Co-authored-by: Félix Malfait <felix@twenty.com>
Co-authored-by: Charles Bochet <charles@twenty.com>

packages/twenty-front/src/modules/ai/utils/groupThreadsByDate.ts

@@ -1,17 +1,17 @@
 import { type AgentChatThread } from '~/generated-metadata/graphql';
 
-export const groupThreadsByDate = (threads: AgentChatThread[]) => {
+import { type DateGroupKey } from '@/ai/utils/dateGroupKey';
+
+export const groupThreadsByDate = (
+  threads: AgentChatThread[],
+): Record<DateGroupKey, AgentChatThread[]> => {
   const today = new Date();
   const yesterday = new Date(today);
   yesterday.setDate(yesterday.getDate() - 1);
 
-  return threads.reduce<{
-    today: AgentChatThread[];
-    yesterday: AgentChatThread[];
-    older: AgentChatThread[];
-  }>(
+  return threads.reduce<Record<DateGroupKey, AgentChatThread[]>>(
     (acc, thread) => {
-      const threadDate = new Date(thread.createdAt);
+      const threadDate = new Date(thread.updatedAt);
       const threadDateString = threadDate.toDateString();
 
       if (threadDateString === today.toDateString()) {