Draw a bot's notice as a notice

m.notice exists so a client can hold it back from the conversation, and
every other msgtype fell through protocol::message_body into a plain
message. In a room with an active bridge that made automated traffic
indistinguishable from people talking (#215).

A notice is still a chat line - it has a sender, it can be replied to
and redacted - so it keeps its place in the timeline and takes its own
kind rather than the grey system stream: muted body, a rail down the
edge that survives grouping, and the word "notice" on the byline, since
a toned-down body can be mistaken for an unlucky one.

It also stops announcing itself while the account's own
.m.rule.suppress_notices override says so, which is the state every
homeserver ships. Read from the real rules rather than assumed: somebody
who turned it off meant to.

Two places called this "chat" literally and greyed out every Matrix
message in an HTML export; both now ask isChatKind.

Co-Authored-By: Claude Opus 5 <[email protected]>

src/renderer/src/app.css

@@ -5877,6 +5877,40 @@ video.lightbox-media {
   font: inherit;
 }
 
+/* --- Notices ---------------------------------------------------------- */
+
+/* Matrix's m.notice: an announcement rather than a sentence. What bots and
+   bridges send, and what a homeserver's own notices arrive as.
+
+   Held back rather than hidden. The body takes the muted ink and the name
+   keeps its colour, so a bridge relaying a hundred build results reads as a
+   hundred announcements while the people talking still stand out - which is
+   the whole reason the msgtype exists. The rule sits on the body alone so a
+   notice that mentions you can still be highlighted over the top of it. */
+.message-row.notice .message-body {
+  color: var(--text-muted);
+}
+
+/* The rail rather than a tag on the byline, because a run of notices is
+   grouped and only the first of a run has a byline to hang anything on -
+   which is exactly the case a bridge produces. */
+.message-row.notice {
+  box-shadow: inset 2px 0 0 var(--border);
+}
+
+.notice-tag {
+  display: inline-flex;
+  align-items: center;
+  gap: 3px;
+  margin-left: var(--spacing-xs);
+  padding: 0 6px;
+  border-radius: 999px;
+  border: 1px solid var(--border);
+  color: var(--text-muted);
+  font-style: normal;
+  text-transform: lowercase;
+}
+
 /* --- Whispers --------------------------------------------------------- */
 
 /* Said privately rather than to the room. Highlighted like a mention, because

src/renderer/src/components/MessageRow.tsx

@@ -42,6 +42,7 @@ import {
   formatTime,
   hasDirectMessages,
   isChatKind,
+  isNotice,
   isReward,
   isWhisper,
   nickColor,
@@ -343,6 +344,11 @@ function MessageRowBody({
   // Said to you rather than to the room. Drawn differently on purpose: the
   // whole risk with a private message is reading it as a public one.
   const whispered = isWhisper(message.kind)
+  // An announcement rather than a sentence. Kept in the conversation and
+  // drawn a shade back from it - the point of m.notice is that a bridge
+  // relaying a hundred build results should not read like a hundred people
+  // talking.
+  const notice = isNotice(message.kind)
   const reward = isReward(message.kind)
   // Both of the modes that draw an avatar column. Bubbles is otherwise
   // nothing like comfy, but it wants the same picture beside the same first
@@ -609,6 +615,7 @@ function MessageRowBody({
           'message-row',
           message.isHighlight && 'highlight',
           whispered && 'whisper',
+          notice && 'notice',
           message.pending && 'pending',
           message.failed && 'failed',
           isSystem && 'system',
@@ -695,6 +702,18 @@ function MessageRowBody({
             </span>
           )}
 
+          {/* Named as well as toned down. The muted body says "less
+              important", which a long or unlucky message can say by accident;
+              the word says what it actually is. Only where there is a byline
+              to put it on - a run of notices is grouped, and the rail down
+              the edge is what carries it there. */}
+          {notice && !grouped && (
+            <span className="notice-tag small">
+              <Icon name="smart_toy" size={11} />
+              <span>notice</span>
+            </span>
+          )}
+
           {/* Said in words as well as in styling. Italics and a tinted edge
               say "not like the others", which is not the same as saying what
               it is - and a private message being mistaken for a public one is

src/renderer/src/lib/exporter.ts

@@ -1,5 +1,5 @@
 import { escapeHtml, extractMedia, formatMessage } from './format'
-import { fileNameOf } from './util'
+import { fileNameOf, isChatKind } from './util'
 import type { Message } from '../../../shared/wire'
 
 /**
@@ -203,7 +203,11 @@ async function renderMessage(
     cards += `<blockquote>${bits.join('<br>')}${link}</blockquote>`
   }
 
-  const system = m.kind && m.kind !== 'chat' ? ' system' : ''
+  // The same question the live view asks, rather than a second answer to it:
+  // "chat" is what IRC, Discord and Sneedchat call a message and "message" is
+  // what Matrix calls one, so a literal comparison greyed out every Matrix
+  // line in an export as though nobody had said it.
+  const system = isChatKind(m.kind) ? '' : ' system'
   const who = m.isAction ? `* ${m.from}` : m.from
   const edited = m.edited ? ' <span class="dim">(edited)</span>' : ''
   return (

src/renderer/src/lib/util.ts

@@ -120,7 +120,21 @@ export function serviceLabel(service: string): string {
  * grey system line with no author or avatar.
  */
 export function isChatKind(kind: string | undefined): boolean {
-  return kind === 'chat' || kind === 'message' || kind === 'whisper'
+  return kind === 'chat' || kind === 'message' || kind === 'whisper' || kind === 'notice'
+}
+
+/**
+ * An announcement rather than a sentence: Matrix's `m.notice`, which is what
+ * bots and bridges send and what a homeserver's own notices arrive as.
+ *
+ * Still a chat line - it has a sender, it can be replied to and redacted, and
+ * it belongs in the conversation rather than in the grey system stream. Only
+ * its weight changes, which is the entire reason the msgtype exists: in a
+ * room with an active bridge, automated traffic drawn like people talking
+ * makes the people impossible to find.
+ */
+export function isNotice(kind: string | undefined): boolean {
+  return kind === 'notice'
 }
 
 /**