feat(expressions): custom emojis and stickers per space

Emojis and stickers get separate tables on purpose: an emoji sits inside a
sentence and a sticker is the whole message, so their sizes, limits and render
paths differ.

Emoji names are unique per space and restricted to letters, digits and
underscore — :name: has to resolve to one image, and a space or colon inside
the name would make the reference impossible to delimit. Sticker names are
labels picked from a grid, so they accept anything.

Rendering reuses the existing markdown pipeline by rewriting :name: into image
syntax, which needs no plugin. Code spans and fences are left alone: text
someone wrapped in backticks was meant to be shown literally, and turning it
into an image would destroy what they wrote.

Messages carry stickerId with ON DELETE set null — removing a sticker from the
space must not delete the history of everyone who used it. The server refuses a
sticker from another space, which would otherwise leak images between unrelated
servers.

Expressions load once per space and stay in memory: the message renderer
consults the map for every :name: it finds, and a request per lookup would turn
each message into a cascade.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

packages/web/src/components/chat/MarkdownRenderer.tsx

@@ -1,4 +1,5 @@
 import React from 'react';
+import { isCustomEmojiAlt } from '../../utils/customEmoji';
 import ReactMarkdown, { defaultUrlTransform } from 'react-markdown';
 import remarkGfm from 'remark-gfm';
 import { Highlight, themes } from 'prism-react-renderer';
@@ -186,7 +187,22 @@ function buildComponents(): Components {
     hr: () => <hr className="border-border-soft my-2" />,
 
     // Images (in markdown content — not attachments)
-    img: ({ src, alt }) => (
+    img: ({ src, alt }) => {
+      // Emoji próprio do espaço chega como imagem markdown com alt `:nome:`.
+      // Renderiza em tamanho de texto e inline, para caber no meio da frase em
+      // vez de virar um bloco como uma imagem comum.
+      if (isCustomEmojiAlt(alt ?? undefined)) {
+        return (
+          <img
+            src={src}
+            alt={alt ?? ''}
+            title={alt ?? ''}
+            className="inline-block align-text-bottom w-[22px] h-[22px] object-contain"
+            loading="lazy"
+          />
+        );
+      }
+      return (
       <div className="mt-1 max-w-[400px]">
         <img
           src={src}
@@ -197,7 +213,8 @@ function buildComponents(): Components {
           crossOrigin="anonymous"
         />
       </div>
-    ),
+      );
+    },
 
     // Tables (GFM)
     table: ({ children }) => (

packages/web/src/components/chat/Message.tsx

@@ -1,4 +1,6 @@
-import React, { useState, useRef, useEffect, useCallback } from 'react';
+import React, { useState, useRef, useEffect, useCallback, useMemo } from 'react';
+import { useExpressionStore } from '../../stores/expressionStore';
+import { renderCustomEmojis } from '../../utils/customEmoji';
 import { api } from '../../api/client';
 import { useT } from '../../i18n';
 import { createPortal } from 'react-dom';
@@ -233,6 +235,26 @@ export function Message({ message, isCompact, isFirstInGroup, previousMessageId
     return () => clearTimeout(confirmDeleteTimeout.current);
   }, []);
 
+  // Emojis próprios do espaço são resolvidos antes do markdown; sem espaço
+  // (DM, por exemplo) o texto passa intacto.
+  const emojiSpaceId = useSpaceStore((s) => s.currentSpaceId);
+  const emojiLookup = useExpressionStore((s) => s.emojiByName);
+  const contentWithEmojis = useMemo(() => {
+    if (!message.content || !emojiSpaceId) return message.content ?? '';
+    return renderCustomEmojis(
+      message.content,
+      (name) => emojiLookup(emojiSpaceId, name),
+      (filename) => api.uploads.url(filename),
+    );
+  }, [message.content, emojiSpaceId, emojiLookup]);
+
+  const stickerId = (message as MessageWithUser).stickerId;
+  const sticker = useExpressionStore((s) =>
+    stickerId && emojiSpaceId
+      ? s.stickersBySpace.get(emojiSpaceId)?.find((k) => k.id === stickerId)
+      : undefined,
+  );
+
   const isGifOnly = isGifOnlyMessage(message.content);
   const imageEmbedSourceUrl = isGifOnly ? null : getImageEmbedSourceUrl(message.content, message.embeds || []);
   // sourceUrl: the original URL for context menu Copy/Open Link actions
@@ -528,7 +550,19 @@ export function Message({ message, isCompact, isFirstInGroup, previousMessageId
               <>
                 {message.content && (
                   <div className="text-txt-message text-[15px] leading-[1.5] break-words whitespace-pre-wrap selection:bg-accent-primary/30">
-                    <MarkdownRenderer content={message.content} />
+                    {sticker ? (
+                      // Figurinha ocupa a mensagem inteira, sem moldura de
+                      // anexo: é o conteúdo, não um arquivo acompanhando texto.
+                      <img
+                        src={api.uploads.url(sticker.filename)}
+                        alt={sticker.name}
+                        title={sticker.name}
+                        className="w-[160px] h-[160px] object-contain rounded-lg"
+                        loading="lazy"
+                      />
+                    ) : (
+                      <MarkdownRenderer content={contentWithEmojis} />
+                    )}
                     {message.editedAt && (
                       <span className="text-[10px] text-txt-tertiary ml-1 select-none font-medium">(edited)</span>
                     )}