Replace custom markdown renderer with react-markdown

- Add react-markdown and remark-gfm dependencies
- Remove hacky regex-based renderMarkdown function
- Full GFM support: tables, task lists, strikethrough, autolinks
- Update CSS for react-markdown output (task lists, blockquotes, hr)
- Cleaner, more maintainable code

1 files changed, 2 insertions, 0 deletions

diff --git a/package.json b/package.json
index a76759a..7bc98e3 100644
--- a/package.json
+++ b/package.json
@@ -47,6 +47,8 @@
     "better-sqlite3": "12.2.0",
     "react": "^19.1.1",
     "react-dom": "^19.1.1",
+    "react-markdown": "^10.1.0",
+    "remark-gfm": "^4.0.1",
     "uuid": "^13.0.0"
   },
   "devDependencies": {