feat(ECR-023): AICoreConfig KnowledgeSource 只读并 Closed

运营可观测知识源目录（knowledge_sources + admin /ai），不含 Chunk/Embedding。

Co-authored-by: Cursor <cursoragent@cursor.com>

apps/api/internal/service/admin/ai_config.go

@@ -11,6 +11,7 @@ import (
 )
 
 var ErrSystemPromptNotFound = errString("system prompt not found")
+var ErrKnowledgeSourceNotFound = errString("knowledge source not found")
 
 // ListSystemPrompts returns SystemPrompt catalog.
 func (s *Service) ListSystemPrompts(ctx context.Context) ([]repository.SystemPromptRow, error) {
@@ -32,3 +33,24 @@ func (s *Service) GetSystemPrompt(ctx context.Context, id uuid.UUID) (*repositor
 	}
 	return row, err
 }
+
+// ListKnowledgeSources returns KnowledgeSource catalog.
+func (s *Service) ListKnowledgeSources(ctx context.Context) ([]repository.KnowledgeSourceRow, error) {
+	items, err := s.Repo.ListKnowledgeSources(ctx)
+	if err != nil {
+		return nil, err
+	}
+	if items == nil {
+		items = []repository.KnowledgeSourceRow{}
+	}
+	return items, nil
+}
+
+// GetKnowledgeSource loads one source.
+func (s *Service) GetKnowledgeSource(ctx context.Context, id uuid.UUID) (*repository.KnowledgeSourceRow, error) {
+	row, err := s.Repo.GetKnowledgeSource(ctx, id)
+	if errors.Is(err, pgx.ErrNoRows) {
+		return nil, ErrKnowledgeSourceNotFound
+	}
+	return row, err
+}