* chore: update copyright year in license headers
* Revert "chore: update copyright year in license headers"
This reverts commit 3e58129c431b9a491089ce36b908f9bb6ba38ed3.
* chore: update copyright year in license headers
* fix: sort go imports
* fix: add missing license headers
refactor: copylocks and staticcheck findings
Refactor mutex handling, optimize byte slice creation, and clean up code in accordance with go.staticcheck and copylocks guidelines.
- Changed AppConfig's mutex to *sync.Mutex, preventing mutex copying and enhancing thread safety.
- Simplified byte slice initialization in writeConfig for efficiency.
- Removed redundant return in DynamicReload for better code clarity.
