Replace multi-page portal with hash-routed SPA, DFTE shell placeholders, and
data-first JSON APIs. Remove legacy routes, root-template override path, and
HTML-derived info pipeline. Add bootstrap feature flags, in-DOM toast/dialog UX,
OTA via POST /u, and tests for shell, bootstrap, API JSON, and captive host rule.
Rewrite README as fork disclaimer and modernization overview.
Replace DEBUG_WM with WiFiManagerLogLevel/log(), optional WiFiManagerLogSink,
and WM_NO_LOG stripping. Add JSON API handlers and shell templates (RootShell,
PortalAppJS). Bridge DFTE logging with owner-scoped teardown; add migrate_debug_wm
helper; document and set WM_LOG_LEVEL in platformio.
alex