Introduced sync.RWMutex to protect concurrent access to configuration
fields (AuthUser, AuthPass, APITokens) that are modified by the
ConfigWatcher at runtime.
- Added global config.Mu RWMutex in internal/config/config.go
- Protected config updates in ConfigWatcher.reloadConfig() and reloadAPITokens()
- Protected config reads in CheckAuth and all API token handlers
- Protected Router.SetConfig() during full config reloads
This prevents race conditions when .env file changes trigger config
reloads while authentication handlers are reading the same fields.