flatten src; mv types .; mv interface types

Put all non-built type declarations to types, including both interface
& helper types.

With types cleaned out of src directory, flatten source code one level
for shorter hierarchy.

src/index.ts

@@ -1,10 +1,10 @@
-import type { Scopes } from "./config/default/scopes.js";
-import scopes from "./config/default/scopes.js";
-import files from "./config/default/files.js";
-import rulesets from "./config/default/rulesets.js";
-import options from "./config/default/options.js";
-import plugins from "./config/default/plugins.js";
-import parsers from "./config/default/parsers.js";
+import type { Scopes } from "./default/scopes.js";
+import scopes from "./default/scopes.js";
+import files from "./default/files.js";
+import rulesets from "./default/rulesets.js";
+import options from "./default/options.js";
+import plugins from "./default/plugins.js";
+import parsers from "./default/parsers.js";
 
 export default function (
   scope: Partial<

tsconfig.json

@@ -4,6 +4,7 @@
   "$schema": "https://json.schemastore.org/tsconfig",
   "include": [
     "src/**/*.ts",
+    "types/**/*.d.ts",
     "*.config.ts",
   ],
   "compilerOptions": {