🐞 fix: Update config file handling

src/config/config.ts

@@ -111,12 +111,21 @@ function camelize(value: unknown): unknown {
   return value;
 }
 
+function objectFromNull(value: unknown): unknown {
+  return value === null ? {} : value;
+}
+
 export function expandHome(path: string): string {
   return path.startsWith('~/') ? resolve(homedir(), path.slice(2)) : path;
 }
 
 export function loadConfigFromString(source: string): AppConfig {
-  const parsed = camelize(YAML.parse(source) ?? {});
+  const parsed = camelize(YAML.parse(source) ?? {}) as Record<string, any>;
+  parsed.newsletters = objectFromNull(parsed.newsletters);
+  parsed.categories = objectFromNull(parsed.categories) as Record<string, any>;
+  if (parsed.categories && typeof parsed.categories === 'object') {
+    parsed.categories.llm = objectFromNull(parsed.categories.llm);
+  }
   return configSchema.parse(parsed);
 }