Remove Gorush, use direct APNs/FCM, fix worker queries

- Remove Gorush push server dependency (now using direct APNs/FCM)
- Update docker-compose.yml to remove gorush service
- Update config.go to remove GORUSH_URL
- Fix worker queries:
  - Use auth_user instead of user_user table
  - Use completed_at instead of completion_date column
- Add NotificationService to worker handler for actionable notifications
- Add docs/PUSH_NOTIFICATIONS.md with architecture documentation
- Update README.md, DOKKU_SETUP.md, and dev.sh

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

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

internal/config/config.go

@@ -60,10 +60,7 @@ type EmailConfig struct {
 }
 
 type PushConfig struct {
-	// Gorush server URL (deprecated - kept for backwards compatibility)
-	GorushURL string
-
-	// APNs (iOS)
+	// APNs (iOS) - uses github.com/sideshow/apns2 for direct APNs communication
 	APNSKeyPath    string
 	APNSKeyID      string
 	APNSTeamID     string
@@ -71,7 +68,7 @@ type PushConfig struct {
 	APNSSandbox    bool
 	APNSProduction bool // If true, use production APNs; if false, use sandbox
 
-	// FCM (Android)
+	// FCM (Android) - uses direct HTTP to FCM legacy API
 	FCMServerKey string
 }
 
@@ -166,7 +163,6 @@ func Load() (*Config, error) {
 			UseTLS:   viper.GetBool("EMAIL_USE_TLS"),
 		},
 		Push: PushConfig{
-			GorushURL:      viper.GetString("GORUSH_URL"),
 			APNSKeyPath:    viper.GetString("APNS_AUTH_KEY_PATH"),
 			APNSKeyID:      viper.GetString("APNS_AUTH_KEY_ID"),
 			APNSTeamID:     viper.GetString("APNS_TEAM_ID"),
@@ -244,7 +240,6 @@ func setDefaults() {
 	viper.SetDefault("DEFAULT_FROM_EMAIL", "Casera <noreply@casera.com>")
 
 	// Push notification defaults
-	viper.SetDefault("GORUSH_URL", "http://localhost:8088")
 	viper.SetDefault("APNS_TOPIC", "com.example.casera")
 	viper.SetDefault("APNS_USE_SANDBOX", true)
 	viper.SetDefault("APNS_PRODUCTION", false)