add regression coverage for overlapping layouts and loaders

merge router-ssr-api-cleanup into main

expand router and hook type-safety coverage

remove router-context test alias and document env splits

define RouterBase as the declared generic router contract

Merge commit 'e15a402' into router-ssr-api-cleanup

skip standalone tracing in negative prerender builds

remove window globals from router and integration tests

redesign router API and add SSR-safe hook exports

switch standalone tracing to nf3

fix standalone tracing for Takumi native deps

docs clarify getLoaderData module-scope usage

fix build output dir resolution for prerender and vercel

use vite BASE_URL instead of custom base define

fix standalone tracing and base-path federation paths