- keep install-mode root redirect to /install and add tests covering install root redirect and install page serving
- change root backend handler from Any("/") to POST("/") so GET / can consistently serve the SPA after install
Co-authored-by: Copilot <copilot@github.com>
- add ShouldSkipSPAFallback() deny prefixes: /api, /admin/api, /payments, /pay
- apply StaticWithConfig Skipper in both main http server and install server
- add unit tests for fallback skip matching behavior