Revert Mithril to v2.2.2

Revert Mithril from v2.3.8 back to v2.2.2 (used in v1.2.13) to fix
regression bugs in the latest version that have not been resolved.

package.json

@@ -46,7 +46,7 @@
     "@types/jsonwebtoken": "^9.0.10",
     "@types/koa": "^2.15.0",
     "@types/koa-compress": "^4.0.7",
-    "@types/mithril": "^2.2.8",
+    "@types/mithril": "^2.2.6",
     "@types/node": "^20.19.37",
     "@types/parsimmon": "^1.10.9",
     "@types/seedrandom": "^3.0.8",
@@ -56,7 +56,7 @@
     "esbuild": "^0.27.4",
     "eslint": "^8.57.1",
     "eslint-config-prettier": "^9.1.2",
-    "mithril": "^2.3.8",
+    "mithril": "2.2.2",
     "prettier": "^3.8.1",
     "sql.js": "^1.14.1",
     "svgo": "^3.3.3",