Upgrade typedoc-github-theme to v0.4.0 and remove local CSS workaround

v0.4.0 includes the typography fixes from upstream PR
JulianWowra/typedoc-github-theme#7, so the local `customCss` override
(`scripts/typedoc-github-theme-fixes.css`) added in 0bbbfee is no
longer needed.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

package-lock.json

@@ -39,7 +39,7 @@
         "ts-to-zod": "^5.1.0",
         "tsx": "^4.21.0",
         "typedoc": "^0.28.14",
-        "typedoc-github-theme": "^0.3.1",
+        "typedoc-github-theme": "^0.4.0",
         "typescript": "^5.9.3",
         "zod": "^4.1.13"
       },
@@ -9210,9 +9210,9 @@
       }
     },
     "node_modules/typedoc-github-theme": {
-      "version": "0.3.1",
-      "resolved": "https://registry.npmjs.org/typedoc-github-theme/-/typedoc-github-theme-0.3.1.tgz",
-      "integrity": "sha512-j6PmkAGmf/MGCzYjQcUH6jS9djPsNl/IoTXooxC+MoeMkBhbmPyKJlpR6Lw12BLoe2OYpYA2J1KMktUJXp/8Sw==",
+      "version": "0.4.0",
+      "resolved": "https://registry.npmjs.org/typedoc-github-theme/-/typedoc-github-theme-0.4.0.tgz",
+      "integrity": "sha512-lo/hr4EFZxq0SsMGeAscKUzljIKFgrJf5fb4nOAJcqaiSShQv7kzwF6M1s2fVRvUyx6UsmD4zEb+MtKkbucYpg==",
       "dev": true,
       "license": "MIT",
       "engines": {