fix(docs): map exact source aliases in built checks

scripts/doc-typecheck-paths.ts

@@ -0,0 +1,11 @@
+/** Map one workspace source alias target to its declaration-build target. */
+export function builtDeclarationPath(candidate: string): string {
+  if (candidate.endsWith('/src')) {
+    return `${candidate.slice(0, -'/src'.length)}/lib/types`
+  }
+  const sourceFile = /^(.*)\/src\/(.+)\.ts$/.exec(candidate)
+  if (sourceFile?.[1] && sourceFile[2]) {
+    return `${sourceFile[1]}/lib/types/${sourceFile[2]}.d.ts`
+  }
+  throw new Error(`doc-typecheck: cannot map workspace source path to built declarations: ${candidate}`)
+}