feat(server): meter AI point usage across tenant AI features

Adds an ai_point_usage_logs ledger and a reserve/refund/complete pipeline
that charges AI points for article selection optimize, template analyze
/title/outline, and KOL prompt generate/optimize. Pending reservations
are reconciled when the kol-assist worker and template-assist tasks
finish or fail, so points refund automatically on errors. Workspace now
exposes the AI quota status and a paginated usage ledger.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

server/internal/tenant/transport/kol_manage_handler.go

@@ -42,7 +42,7 @@ func NewKolManageHandler(a *bootstrap.App, assets *AssetHandler) *KolManageHandl
 		profileSvc: profileSvc,
 		pkgSvc:     app.NewKolPackageService(profileSvc, a.KolPackages, a.KolPrompts).WithCache(a.Cache),
 		promptSvc:  app.NewKolPromptService(a.DB, profileSvc, a.KolPackages, a.KolPrompts, a.KolSubscriptions, a.KolPromptAsset).WithCache(a.Cache),
-		assistSvc:  app.NewKolAssistService(profileSvc, a.KolAssists, a.LLM, a.RabbitMQ, a.Config.LLM, a.Logger),
+		assistSvc:  app.NewKolAssistService(a.DB, profileSvc, a.KolAssists, a.LLM, a.RabbitMQ, a.Config.LLM, a.Logger).WithCache(a.Cache),
 		assets:     assets,
 	}
 }