v0.25.0 — Debug page: operator testing & diagnostics dashboard

Debug-mode-only dashboard (/debug) with 8 collapsible sections:
system diagnostics, notification testing, backup triggers, storage
simulation, hub & connectivity, self-update dry-run, DR/setup wizard,
and in-memory log viewer. Migrates debug dump from API router to web
server. Adds ring buffer log capture, storage disconnect simulation,
event history tracking, and cross-drive/self-update test methods.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

controller/internal/web/handlers.go

@@ -97,6 +97,7 @@ func (s *Server) baseData(page, title string) map[string]interface{} {
 		"Domain":       s.cfg.Customer.Domain,
 		"Version":      s.version,
 		"AuthEnabled":  s.authEnabled(),
+		"DebugMode":    s.isDebug(),
 	}
 	if s.alertManager != nil {
 		data["Alerts"] = s.alertManager.GetAlerts()