feat(kol): enrich assist generate with URL references and template prompt

- Add kolAssistURLResolver that fetches reference articles via the Ark
  URL extractor when the user's description contains http(s) links, and
  merges up to kolAssistReferenceContentMaxRunes of extracted content
  into the generate description.
- Rewrite the generate user prompt into a strict template-authoring
  brief: output only the final prompt template in Chinese, parameterize
  variable info as {{placeholder}}, require at least 3 placeholders
  when references exist, and cover goal/topic/title/structure/style/
  interaction/constraints.
- Wire LLMConfig and logger through NewKolAssistService and the
  handler.

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

server/internal/tenant/app/kol_assist_service.go

@@ -8,10 +8,12 @@ import (
 	"github.com/google/uuid"
 
 	"github.com/geo-platform/tenant-api/internal/shared/auth"
+	"github.com/geo-platform/tenant-api/internal/shared/config"
 	"github.com/geo-platform/tenant-api/internal/shared/llm"
 	"github.com/geo-platform/tenant-api/internal/shared/messaging/rabbitmq"
 	"github.com/geo-platform/tenant-api/internal/shared/response"
 	"github.com/geo-platform/tenant-api/internal/tenant/repository"
+	"go.uber.org/zap"
 )
 
 const (
@@ -46,10 +48,12 @@ type KolAssistTaskResponse struct {
 }
 
 type KolAssistService struct {
-	profileSvc *KolProfileService
-	repo       repository.KolAssistRepository
-	llm        llm.Client
-	messaging  *rabbitmq.Client
+	profileSvc  *KolProfileService
+	repo        repository.KolAssistRepository
+	llm         llm.Client
+	messaging   *rabbitmq.Client
+	logger      *zap.Logger
+	urlResolver *kolAssistURLResolver
 }
 
 func NewKolAssistService(
@@ -57,12 +61,16 @@ func NewKolAssistService(
 	repo repository.KolAssistRepository,
 	llmClient llm.Client,
 	messagingClient *rabbitmq.Client,
+	llmCfg config.LLMConfig,
+	logger *zap.Logger,
 ) *KolAssistService {
 	return &KolAssistService{
-		profileSvc: profileSvc,
-		repo:       repo,
-		llm:        llmClient,
-		messaging:  messagingClient,
+		profileSvc:  profileSvc,
+		repo:        repo,
+		llm:         llmClient,
+		messaging:   messagingClient,
+		logger:      logger,
+		urlResolver: newKolAssistURLResolver(llmCfg, logger),
 	}
 }