feat: enhance Safew watcher initialization and token management

- Added functionality to list and start Safew tokens in the main server function, ensuring proper initialization of the Safew watcher.
- Introduced `ensureSafewWatcher` method in the ChannelHandler to manage Safew tokens during channel creation and updates.
- Implemented `StartTokens` method in the Watcher to handle multiple tokens efficiently.
- Enhanced error handling and logging for Safew watcher operations to improve observability.

internal/store/channel.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
+	"strings"
 
 	"aiaa-notification-service/internal/model"
 )
@@ -94,3 +95,38 @@ func (s *Store) DeleteChannel(ctx context.Context, id int) error {
 	}
 	return nil
 }
+
+func (s *Store) ListSafewTokens(ctx context.Context) ([]string, error) {
+	rows, err := s.DB.QueryContext(ctx, `SELECT config FROM notification_channel WHERE type = 'safew'`)
+	if err != nil {
+		return nil, fmt.Errorf("list safew tokens: %w", err)
+	}
+	defer rows.Close()
+	seen := map[string]struct{}{}
+	var tokens []string
+	for rows.Next() {
+		var configBytes []byte
+		if err := rows.Scan(&configBytes); err != nil {
+			return nil, fmt.Errorf("scan safew config: %w", err)
+		}
+		var cfg struct {
+			Token string `json:"token"`
+		}
+		if err := json.Unmarshal(configBytes, &cfg); err != nil {
+			continue
+		}
+		tok := strings.TrimSpace(cfg.Token)
+		if tok == "" {
+			continue
+		}
+		if _, ok := seen[tok]; ok {
+			continue
+		}
+		seen[tok] = struct{}{}
+		tokens = append(tokens, tok)
+	}
+	if tokens == nil {
+		tokens = []string{}
+	}
+	return tokens, rows.Err()
+}