chore(deps): sanitize-html 2.18.1, i18next-http-backend 4.0.3 [security]

Matches upstream Cinny 4.12.8. npm audit flagged our sanitize-html
2.17.7 with three advisories, two of them XSS bypasses (SMIL animation
namespace-prefix javascript: URIs; meta refresh javascript:/data: URLs;
noscript content rendering after an implied close). sanitize-html cleans
formatted message HTML. After the bump: 0 production advisories.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_017PCb59uY3UKqDqt7B6hzd5

package.json

@@ -72,7 +72,7 @@
     "html-react-parser": "6.1.2",
     "i18next": "26.2.0",
     "i18next-browser-languagedetector": "8.2.1",
-    "i18next-http-backend": "4.0.2",
+    "i18next-http-backend": "4.0.3",
     "immer": "11.1.8",
     "is-hotkey": "0.2.0",
     "jotai": "2.20.0",
@@ -97,7 +97,7 @@
     "react-i18next": "17.0.8",
     "react-range": "1.10.0",
     "react-router-dom": "7.18.3",
-    "sanitize-html": "2.17.7",
+    "sanitize-html": "2.18.1",
     "slate": "0.124.1",
     "slate-dom": "0.124.1",
     "slate-history": "0.113.1",