Add Stationery and Stationery Dark themes with notebook chrome.

Manila folders, ruled chat, post-it nav, and folder tabs; dark variant uses Catppuccin Mocha colors with muted stickies and soft glows.

src/app/components/message/layout/Base.tsx

@@ -1,7 +1,9 @@
-import React from 'react';
+import React, { CSSProperties, useMemo } from 'react';
 import { Text, as } from 'folds';
 import classNames from 'classnames';
 import * as css from './layout.css';
+import { isStationeryTheme, useTheme } from '../../../hooks/useTheme';
+import { STATIONERY_NAME_INK } from '../../../utils/paperSafeInk';
 
 export const MessageBase = as<'div', css.MessageBaseVariants>(
   ({ className, highlight, selected, collapse, autoCollapse, space, newMessage, ...props }, ref) => (
@@ -10,6 +12,7 @@ export const MessageBase = as<'div', css.MessageBaseVariants>(
         css.MessageBase({ highlight, selected, collapse, autoCollapse, space, newMessage }),
         className
       )}
+      data-message-collapsed={collapse ? '' : undefined}
       {...props}
       ref={ref}
     />
@@ -17,12 +20,45 @@ export const MessageBase = as<'div', css.MessageBaseVariants>(
 );
 
 export const AvatarBase = as<'span'>(({ className, ...props }, ref) => (
-  <span className={classNames(css.AvatarBase, className)} {...props} ref={ref} />
+  <span
+    className={classNames(css.AvatarBase, className)}
+    data-message-avatar=""
+    {...props}
+    ref={ref}
+  />
 ));
 
-export const Username = as<'span'>(({ as: AsUsername = 'span', className, ...props }, ref) => (
-  <AsUsername className={classNames(css.Username, className)} {...props} ref={ref} />
-));
+export const Username = as<'span'>(({ as: AsUsername = 'span', className, style, ...props }, ref) => {
+  const theme = useTheme();
+  const isStationery = isStationeryTheme(theme);
+  const userColor =
+    typeof (style as CSSProperties | undefined)?.color === 'string'
+      ? ((style as CSSProperties).color as string)
+      : undefined;
+
+  const safeStyle = useMemo((): CSSProperties | undefined => {
+    if (!isStationery) return style as CSSProperties | undefined;
+    return {
+      ...(style as CSSProperties | undefined),
+      // Name in ink; keep their color as an accent underline
+      color: STATIONERY_NAME_INK,
+      ...(userColor
+        ? { ['--username-accent' as string]: userColor, textDecorationColor: userColor }
+        : null),
+    };
+  }, [style, isStationery, userColor]);
+
+  return (
+    <AsUsername
+      className={classNames(css.Username, className)}
+      data-message-username=""
+      data-username-accent={isStationery && userColor ? '' : undefined}
+      style={safeStyle}
+      {...props}
+      ref={ref}
+    />
+  );
+});
 
 export const UsernameBold = as<'b'>(({ as: AsUsernameBold = 'b', className, ...props }, ref) => (
   <AsUsernameBold className={classNames(css.UsernameBold, className)} {...props} ref={ref} />
@@ -36,6 +72,8 @@ export const MessageTextBody = as<'div', css.MessageTextBodyVariants & { notice?
       priority={notice ? '300' : '400'}
       className={classNames(css.MessageTextBody({ preWrap, jumboEmoji, emote }), className)}
       data-allow-text-selection="true"
+      data-message-body=""
+      data-jumbo-emoji={jumboEmoji ? '' : undefined}
       {...props}
       ref={ref}
     />