remove unnecessary data migration and dead DevelopmentMode config

- Remove retry→http data migration from migrate() — no databases exist pre-1.0
- Remove unused DevelopmentMode field and DEVELOPMENT_MODE env var from config
- Remove DevelopmentMode from config log output (dead code cleanup)

internal/config/config.go

@@ -34,7 +34,6 @@ type Config struct {
 	DataDir         string
 	Debug           bool
 	MaintenanceMode bool
-	DevelopmentMode bool
 	Environment     string
 	MetricsPassword string
 	MetricsUsername string
@@ -101,7 +100,6 @@ func New(lc fx.Lifecycle, params ConfigParams) (*Config, error) {
 		DataDir:         envString("DATA_DIR"),
 		Debug:           envBool("DEBUG", false),
 		MaintenanceMode: envBool("MAINTENANCE_MODE", false),
-		DevelopmentMode: envBool("DEVELOPMENT_MODE", false),
 		Environment:     environment,
 		MetricsUsername: envString("METRICS_USERNAME"),
 		MetricsPassword: envString("METRICS_PASSWORD"),
@@ -131,7 +129,6 @@ func New(lc fx.Lifecycle, params ConfigParams) (*Config, error) {
 		"port", s.Port,
 		"debug", s.Debug,
 		"maintenanceMode", s.MaintenanceMode,
-		"developmentMode", s.DevelopmentMode,
 		"dataDir", s.DataDir,
 		"hasSentryDSN", s.SentryDSN != "",
 		"hasMetricsAuth", s.MetricsUsername != "" && s.MetricsPassword != "",