chore(lint): update mnd name, remove deprecated directives

[meowgorithm]

Linter output for this change:

• The linter "deadcode" is deprecated (step 2) and deactivated. It should be removed from the list of disabled linters. https://golangci-lint.run/product/roadmap/#linter-deprecation-cycle
• The linter "structcheck" is deprecated (step 2) and deactivated. It should be removed from the list of disabled linters. https://golangci-lint.run/product/roadmap/#linter-deprecation-cycle
• The linter "varcheck" is deprecated (step 2) and deactivated. It should be removed from the list of disabled linters. https://golangci-lint.run/product/roadmap/#linter-deprecation-cycle
• The linter 'gomnd' is deprecated (since v1.58.0) due to: The linter has been renamed. Replaced by mnd.