Fix push notifications and hide action button on completed tasks

- Add push_certs directory to Dockerfile for APNs support
- Fix notification_id conversion using strconv.FormatUint instead of string(rune())
- Remove "view" from completed tasks button_types so action button is hidden

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

internal/services/notification_service.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"encoding/json"
 	"errors"
+	"strconv"
 
 	"gorm.io/gorm"
 
@@ -120,7 +121,7 @@ func (s *NotificationService) CreateAndSendNotification(ctx context.Context, use
 			pushData[k] = string(jsonVal)
 		}
 	}
-	pushData["notification_id"] = string(rune(notification.ID))
+	pushData["notification_id"] = strconv.FormatUint(uint64(notification.ID), 10)
 
 	// Send push notification
 	if s.pushClient != nil {