refactor(config): improve ConfigManager API and loading flow

[devspexx]

Overview

Refactors and improves the configuration management API with a focus on safety, clarity, and structured loading behavior.

Changes

• Introduced structured config loading results (ConfigLoadResult, ConfigLoadStatus)
• Improved ConfigManager API:
  • clearer separation between get, load, and create operations
  • added safe tryLoad and tryCreate methods
• Added internal loading flow (loadInternal) to centralize logic
• Improved file handling and directory creation logic
• Refactored method naming for better readability and intent

YamlConfig Improvements

• Added safe typed access methods using Optional
• Added default-based getters (getXOrDefault)
• Eliminated silent fallback issues from Bukkit API

Build / Docs

• Fixed Javadoc doclint issues (build was failing)
• Standardized documentation across all public APIs

Versioning

• Migrated to semantic versioning (1.1.0)

Notes

• No breaking changes to existing usage
• Internal structure significantly improved for future extensions