FEATURE: Mobile Chat Footer Redesign (#25161)

This update adds three tabs to the bottom of the chat overlay to make it easier for users to navigate chat on mobile.

As a result of this change:

- Direct Messages are now shown separately from public channels on mobile
- My Threads has now moved from the channel list to it's own tab on mobile
- My Threads can still be accessed on desktop via the sidebar and within the drawer channel list
- Chat back button has been updated to navigate to the correct tab (for both channels and threads)

Some special cases:

- If DMs are not used then the tab is not rendered
- If the user has no threads then the tab is not rendered
- If both the tabs for DMs and Threads aren't available then the whole footer will not be rendered
- Chat footer is only shown on the listing pages (DMs, Channels, My Threads)

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Co-authored-by: chapoi <101828855+chapoi@users.noreply.github.com>
Co-authored-by: Joffrey JAFFEUX <j.jaffeux@gmail.com>

plugins/chat/config/routes.rb

@@ -6,6 +6,7 @@ Chat::Engine.routes.draw do
     get "/channels" => "channels#index"
     get "/me/channels" => "current_user_channels#index"
     get "/me/threads" => "current_user_threads#index"
+    get "/me/threads/count" => "current_user_threads#thread_count"
     post "/channels" => "channels#create"
     put "/channels/read/" => "reads#update_all"
     put "/channels/:channel_id/read/:message_id" => "reads#update"
@@ -73,6 +74,8 @@ Chat::Engine.routes.draw do
 
   # chat_controller routes
   get "/" => "chat#respond"
+  get "/direct-messages" => "chat#respond"
+  get "/channels" => "chat#respond"
   get "/threads" => "chat#respond"
   get "/browse" => "chat#respond"
   get "/browse/all" => "chat#respond"