fix: bump feedparser to 6.0.11 for Python 3.13+ startup

feedparser 6.0.10 imports the removed stdlib cgi module, which crashes backend startup on Python 3.13 and 3.14 (fixes #437).

Co-authored-by: Cursor <cursoragent@cursor.com>

backend/pyproject.toml

@@ -16,7 +16,7 @@ dependencies = [
     "cryptography>=46.0.7",
     "defusedxml>=0.7.1",
     "fastapi==0.136.3",
-    "feedparser==6.0.10",
+    "feedparser==6.0.11",
     "httpx==0.28.1",
     "playwright==1.59.0",
     "playwright-stealth==1.0.6",