feat: add knowledge management functionality with CRUD operations and database schema

- Implemented KnowledgeHandler for managing knowledge groups and items, including listing, creating, updating, and deleting operations.
- Added database migration scripts to create necessary tables for knowledge management, including knowledge_groups, knowledge_items, knowledge_parse_tasks, and knowledge_chunks_meta.
- Introduced prompt_rule_knowledge_groups table to associate prompt rules with knowledge groups.

server/internal/shared/objectstorage/client.go

@@ -0,0 +1,56 @@
+package objectstorage
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"strings"
+
+	"go.uber.org/zap"
+
+	"github.com/geo-platform/tenant-api/internal/shared/config"
+)
+
+var ErrNotConfigured = errors.New("object storage is not configured")
+
+type Client interface {
+	Validate() error
+	PutBytes(ctx context.Context, objectKey string, content []byte, contentType string) error
+	GetBytes(ctx context.Context, objectKey string) ([]byte, error)
+	Delete(ctx context.Context, objectKey string) error
+}
+
+func New(cfg config.ObjectStorageConfig, logger *zap.Logger) Client {
+	provider := strings.ToLower(strings.TrimSpace(cfg.Provider))
+	switch provider {
+	case "", "disabled":
+		return disabledClient{reason: "object storage is disabled"}
+	case "minio":
+		return NewMinIOClient(cfg, logger)
+	default:
+		return disabledClient{reason: fmt.Sprintf("unsupported object storage provider %q", cfg.Provider)}
+	}
+}
+
+type disabledClient struct {
+	reason string
+}
+
+func (c disabledClient) Validate() error {
+	if c.reason == "" {
+		c.reason = "missing object storage configuration"
+	}
+	return fmt.Errorf("%w: %s", ErrNotConfigured, c.reason)
+}
+
+func (c disabledClient) PutBytes(context.Context, string, []byte, string) error {
+	return c.Validate()
+}
+
+func (c disabledClient) GetBytes(context.Context, string) ([]byte, error) {
+	return nil, c.Validate()
+}
+
+func (c disabledClient) Delete(context.Context, string) error {
+	return c.Validate()
+}