feat: Resend the last 10 messages to new broadcast member

[Hocuri]

Based on #7854, with the following changes:

• Refactor and simplify code, don't reuse the existing get_chat_msgs() function
• Document that Param::Arg4 is also used for resent messages cc818d9
• It's unclear how exactly to resend webxdc status updates. After discussing with @r10s, don't resend webxdc's at all for now. 38d57eb
• Don't set fake msg_id in resent messages e7d0687
  Setting the msg_id to u32::MAX is hacky, and may just as well break
  things as it may fix things, because some code may use the msg.id to
  load information from the database, like get_iroh_topic_for_msg().
  From reading the code, I couldn't find any problem with leaving the
  correct msg_id, and if there is one, then we should add a function
  parameter is_resending that is checked in the corresponding places.

Easiest to review file-by-file rather than individual commits, probably. I'll squash-merge this.

[Hocuri]

Let's do this in a follow-up PR

[r10s]

in practise, resent messages always belong to the same chat, in a channel, but also when resend manually by selecting in the UI

we can also move the event out of the loop, and document that all messages shall belong to the same chat

but i am also fine to leave things as is

[Hocuri]

This could be fixed in this way:

diff --git a/src/chat.rs b/src/chat.rs
index 966a041ca..1b6440720 100644
--- a/src/chat.rs
+++ b/src/chat.rs
@@ -4747,6 +4747,9 @@ pub(crate) async fn resend_msgs_ex(
         msgs.push(msg)
     }
 
+    let mut chat_ids: Vec<ChatId> = msgs.iter().map(|m| m.chat_id).collect();
+    chat_ids.dedup();
+
     for mut msg in msgs {
         match msg.get_state() {
             // `get_state()` may return an outdated `OutPending`, so update anyway.
@@ -4776,9 +4779,6 @@ pub(crate) async fn resend_msgs_ex(
             chat_id: msg.chat_id,
             msg_id: msg.id,
         });
-        // The event only matters if the message is last in the chat.
-        // But it's probably too expensive check, and UIs anyways need to debounce.
-        chatlist_events::emit_chatlist_item_changed(context, msg.chat_id);
 
         if msg.viewtype == Viewtype::Webxdc {
             let conn_fn = |conn: &mut rusqlite::Connection| {
@@ -4811,6 +4811,11 @@ pub(crate) async fn resend_msgs_ex(
         }
         context.scheduler.interrupt_smtp().await;
     }
+    for chat_id in chat_ids {
+        // The event only matters if the message is last in the chat.
+        // But it's probably too expensive check, and UIs anyways need to debounce.
+        chatlist_events::emit_chatlist_item_changed(context, chat_id);
+    }
     Ok(())
 }

but is unrelated to the PR here