feat(web): per-Series detail page keyed by site:series_id (#144)

backend/internal/web/admin.go

@@ -27,6 +27,8 @@ type adminView struct {
 	// the Readers they may act on.
 	OwnerID int64
 	Lanes   lanesView
+	// Detail is the per-Series page data; zero on every other page.
+	Detail seriesDetailView
 }
 
 // lanesView is the Lane status block: one row per Site that has run, plus the
@@ -89,6 +91,7 @@ func (h *Handler) adminRoutes() []adminRoute {
 		{"GET /admin/lanes", h.adminLanes},
 		{"GET /admin/readers", h.adminReaders},
 		{"GET /admin/series", h.adminSeries},
+		{"GET /admin/series/{key}", h.adminSeriesDetail},
 		{"GET /ui/admin/lanes", h.uiLanes},
 		{"POST /readers/{id}/revoke", h.revokeReaderSessions},
 		{"POST /readers/{id}/clear-marks", h.clearReaderMarks},