fix(markdown): render single newlines as line breaks

Add remark-breaks plugin to render single newlines as <br> tags,
matching GitHub Flavored Markdown behavior.

Fixes https://github.com/usememos/memos/issues/5277

🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>

web/package.json

@@ -56,6 +56,7 @@
     "react-simple-pull-to-refresh": "^1.3.3",
     "react-use": "^17.6.0",
     "rehype-raw": "^7.0.0",
+    "remark-breaks": "^4.0.0",
     "remark-gfm": "^4.0.1",
     "tailwind-merge": "^3.4.0",
     "tailwindcss": "^4.1.17",

web/pnpm-lock.yaml

@@ -146,6 +146,9 @@ importers:
       rehype-raw:
         specifier: ^7.0.0
         version: 7.0.0
+      remark-breaks:
+        specifier: ^4.0.0
+        version: 4.0.0
       remark-gfm:
         specifier: ^4.0.1
         version: 4.0.1
@@ -2258,6 +2261,9 @@ packages:
   mdast-util-mdxjs-esm@2.0.1:
     resolution: {integrity: sha512-EcmOpxsZ96CvlP03NghtH1EsLtr0n9Tm4lPUJUBccV9RwUOneqSycg19n5HGzCf+10LozMRSObtVr3ee1WoHtg==}
 
+  mdast-util-newline-to-break@2.0.0:
+    resolution: {integrity: sha512-MbgeFca0hLYIEx/2zGsszCSEJJ1JSCdiY5xQxRcLDDGa8EPvlLPupJ4DSajbMPAnC0je8jfb9TiUATnxxrHUog==}
+
   mdast-util-phrasing@4.1.0:
     resolution: {integrity: sha512-TqICwyvJJpBwvGAMZjj4J2n0X8QWp21b9l0o7eXyVJ25YNWYbJDVIyD1bZXE6WtV6RmKJVYmQAKWa0zWOABz2w==}
 
@@ -2611,6 +2617,9 @@ packages:
   rehype-raw@7.0.0:
     resolution: {integrity: sha512-/aE8hCfKlQeA8LmyeyQvQF3eBiLRGNlfBJEvWH7ivp9sBqs7TNqBL5X3v157rM4IFETqDnIOO+z5M/biZbo9Ww==}
 
+  remark-breaks@4.0.0:
+    resolution: {integrity: sha512-IjEjJOkH4FuJvHZVIW0QCDWxcG96kCq7An/KVH2NfJe6rKZU2AsHeB3OEjPNRxi4QC34Xdx7I2KGYn6IpT7gxQ==}
+
   remark-gfm@4.0.1:
     resolution: {integrity: sha512-1quofZ2RQ9EWdeN34S79+KExV1764+wCUGop5CPL1WGdD0ocPpu91lzPGbwWMECpEpd42kJGQwzRfyov9j4yNg==}
 
@@ -5022,6 +5031,11 @@ snapshots:
     transitivePeerDependencies:
       - supports-color
 
+  mdast-util-newline-to-break@2.0.0:
+    dependencies:
+      '@types/mdast': 4.0.4
+      mdast-util-find-and-replace: 3.0.2
+
   mdast-util-phrasing@4.1.0:
     dependencies:
       '@types/mdast': 4.0.4
@@ -5548,6 +5562,12 @@ snapshots:
       hast-util-raw: 9.1.0
       vfile: 6.0.3
 
+  remark-breaks@4.0.0:
+    dependencies:
+      '@types/mdast': 4.0.4
+      mdast-util-newline-to-break: 2.0.0
+      unified: 11.0.5
+
   remark-gfm@4.0.1:
     dependencies:
       '@types/mdast': 4.0.4

web/src/components/MemoContent/index.tsx

@@ -2,6 +2,7 @@ import { observer } from "mobx-react-lite";
 import { memo, useEffect, useRef, useState } from "react";
 import ReactMarkdown from "react-markdown";
 import rehypeRaw from "rehype-raw";
+import remarkBreaks from "remark-breaks";
 import remarkGfm from "remark-gfm";
 import useCurrentUser from "@/hooks/useCurrentUser";
 import { cn } from "@/lib/utils";
@@ -98,7 +99,7 @@ const MemoContent = observer((props: Props) => {
           onDoubleClick={onMemoContentDoubleClick}
         >
           <ReactMarkdown
-            remarkPlugins={[remarkGfm, remarkTag, remarkPreserveType]}
+            remarkPlugins={[remarkGfm, remarkBreaks, remarkTag, remarkPreserveType]}
             rehypePlugins={[rehypeRaw]}
             components={{
               // Conditionally render custom components based on AST node type