refactor: move CustomElement interface to types.d.ts

src/main.ts

@@ -1,8 +1,3 @@
-interface CustomElement extends HTMLElement {
-	setState(key_path: string, value: unknown): void
-	getState(key_path: string): unknown
-}
-
 interface ComponentOptions {
 	tag: string
 	template: string

src/types.d.ts

@@ -0,0 +1,4 @@
+interface CustomElement extends HTMLElement {
+	setState(key_path: string, value: unknown): void
+	getState(key_path: string): unknown
+}