Replace Gorush with direct APNs/FCM integration

- Add direct APNs client using sideshow/apns2 for iOS push
- Add direct FCM client using legacy HTTP API for Android push
- Remove Gorush dependency (no external push server needed)
- Update all services/handlers to use new push.Client
- Update config for APNS_PRODUCTION flag

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

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

internal/push/client.go

@@ -0,0 +1,113 @@
+package push
+
+import (
+	"context"
+
+	"github.com/rs/zerolog/log"
+
+	"github.com/treytartt/casera-api/internal/config"
+)
+
+// Platform constants
+const (
+	PlatformIOS     = "ios"
+	PlatformAndroid = "android"
+)
+
+// Client provides a unified interface for sending push notifications
+type Client struct {
+	apns *APNsClient
+	fcm  *FCMClient
+}
+
+// NewClient creates a new unified push notification client
+func NewClient(cfg *config.PushConfig) (*Client, error) {
+	client := &Client{}
+
+	// Initialize APNs client (iOS)
+	if cfg.APNSKeyPath != "" && cfg.APNSKeyID != "" && cfg.APNSTeamID != "" {
+		apnsClient, err := NewAPNsClient(cfg)
+		if err != nil {
+			log.Warn().Err(err).Msg("Failed to initialize APNs client - iOS push disabled")
+		} else {
+			client.apns = apnsClient
+			log.Info().Msg("APNs client initialized successfully")
+		}
+	} else {
+		log.Warn().Msg("APNs not configured - iOS push disabled")
+	}
+
+	// Initialize FCM client (Android)
+	if cfg.FCMServerKey != "" {
+		fcmClient, err := NewFCMClient(cfg)
+		if err != nil {
+			log.Warn().Err(err).Msg("Failed to initialize FCM client - Android push disabled")
+		} else {
+			client.fcm = fcmClient
+			log.Info().Msg("FCM client initialized successfully")
+		}
+	} else {
+		log.Warn().Msg("FCM not configured - Android push disabled")
+	}
+
+	return client, nil
+}
+
+// SendToIOS sends a push notification to iOS devices
+func (c *Client) SendToIOS(ctx context.Context, tokens []string, title, message string, data map[string]string) error {
+	if c.apns == nil {
+		log.Warn().Msg("APNs client not initialized, skipping iOS push")
+		return nil
+	}
+	return c.apns.Send(ctx, tokens, title, message, data)
+}
+
+// SendToAndroid sends a push notification to Android devices
+func (c *Client) SendToAndroid(ctx context.Context, tokens []string, title, message string, data map[string]string) error {
+	if c.fcm == nil {
+		log.Warn().Msg("FCM client not initialized, skipping Android push")
+		return nil
+	}
+	return c.fcm.Send(ctx, tokens, title, message, data)
+}
+
+// SendToAll sends a push notification to both iOS and Android devices
+func (c *Client) SendToAll(ctx context.Context, iosTokens, androidTokens []string, title, message string, data map[string]string) error {
+	var lastErr error
+
+	if len(iosTokens) > 0 {
+		if err := c.SendToIOS(ctx, iosTokens, title, message, data); err != nil {
+			log.Error().Err(err).Msg("Failed to send iOS notifications")
+			lastErr = err
+		}
+	}
+
+	if len(androidTokens) > 0 {
+		if err := c.SendToAndroid(ctx, androidTokens, title, message, data); err != nil {
+			log.Error().Err(err).Msg("Failed to send Android notifications")
+			lastErr = err
+		}
+	}
+
+	return lastErr
+}
+
+// IsIOSEnabled returns true if iOS push is configured
+func (c *Client) IsIOSEnabled() bool {
+	return c.apns != nil
+}
+
+// IsAndroidEnabled returns true if Android push is configured
+func (c *Client) IsAndroidEnabled() bool {
+	return c.fcm != nil
+}
+
+// HealthCheck checks if the push services are available
+func (c *Client) HealthCheck(ctx context.Context) error {
+	// For direct clients, we can't easily health check without sending a notification
+	// Return nil if at least one platform is configured
+	if c.apns != nil || c.fcm != nil {
+		return nil
+	}
+	return nil
+}