add community ui

docs/community-messages-panel-plan.md

@@ -147,6 +147,9 @@ crates/community_ui/src/lib.rs      init + CommunityPanel
 crates/community_ui/src/message.rs  one message row's rendering
 ```
 
+`community` re-exports the types the panel names, as `chat` already does for
+`Message`: `ChatMessage`, `ReplyRef`, `ChannelId`, `CommunityId`.
+
 ```rust
 pub fn init(community: Entity<Community>, window: &mut Window, cx: &mut App) -> Entity<CommunityPanel>;
 
@@ -156,11 +159,10 @@ pub struct CommunityPanel {
     community: WeakEntity<Community>,
     channel: Option<ChannelId>,            // the selected channel
     messages: Vec<ChatMessage>,            // ascending, bottom-aligned list
-    message_index: HashMap<EventId, usize>,
     list_state: ListState,
     input: Entity<TextareaState>,
     tasks: Vec<Task<Result<()>>>,
-    subscriptions: SmallVec<[Subscription; 2]>,
+    _subscriptions: SmallVec<[Subscription; 2]>,
 }
 ```
 
@@ -168,18 +170,19 @@ pub struct CommunityPanel {
   `cx.subscribe_in(&community, window, ...)` while it has it, and keeps only the
   weak handle afterwards (`ChatPanel::subscribe_room_events` is the same split).
   It picks `channels().first()` (the genesis `#general`) and, in the subscription,
-  `CommunityEvent::Updated(id)` reloads the open channel while
-  `CommunityEvent::Error(error)` becomes a window notification. A `cx.defer_in` does
-  the first `backfill` + `messages` load, exactly as `ChatPanel::new` defers `connect`.
+  `CommunityEvent::Updated(id)` reloads the open channel through `cx.defer_in`,
+  because the emit sits inside the community's own update; `CommunityEvent::Error(error)`
+  becomes a window notification. A `cx.defer_in` does the first `backfill` + `messages`
+  load, exactly as `ChatPanel::new` defers `connect`.
 - The channel and member lists are read live in `render` through the weak entity
   (as the sidebar reads `Community::channels()`), so a new channel or member needs no
   invalidation; a dropped entity renders an empty state instead.
 - `select_channel(channel, window, cx)` swaps the selection, resets the list and
   loads: `backfill` once per channel, then `messages`.
-- `reload(cx)` awaits `community.messages(&channel, cx)`, replaces `messages`,
-  rebuilds `message_index` and `list_state.reset(len)` (then `scroll_to_end`).
-  Edits, deletes and reactions are folded server-side of the UI, so a full replace
-  is the honest update and stays small at `MESSAGE_LIMIT`.
+- `reload(cx)` awaits `community.messages(&channel, cx)`, replaces `messages` and
+  `list_state.reset(len)` (then `scroll_to_end`). Edits, deletes and reactions are
+  folded server-side of the UI, so a full replace is the honest update and stays
+  small at `MESSAGE_LIMIT`. A failed load becomes a window notification.
 - `send(window, cx)` reads `self.input`, calls `community.send(...)`, clears the
   input, and reloads when the task resolves. Empty input is refused with a
   notification, like `ChatPanel`.
@@ -194,7 +197,7 @@ pub struct CommunityPanel {
     `message::render(...)` and `Scrollbar::vertical(&self.list_state)`, then the
     composer row: `Textarea` (`InputEvent::PressEnter` sends) and a
     `Button::new("send").icon(IconName::PaperPlaneFill)`.
-- A message row: author name (person profile, "Unknown" fallback), `at_ago()` from
+- A message row: author name (person profile, "Unknown" fallback), `to_ago()` from
   `common::TimestampExt`, the content as plain text (no markdown, media or file
   rendering in this pass), a muted `(edited)` marker when `edited_at` is set, an
   emoji summary line from `reactions`, and `"Message deleted"` in