Migrate golangci-lint to v2

[pellared]

Migrate the project to use golangci-lint v2. Update all relevant configuration, CI workflows, and documentation to support the new version.

Steps:

• Update golangci-lint version in go.mod
• Adjust any lint rules or settings for compatibility with v2.
• Test the linting locally and in CI to ensure proper operation.
• Update documentation referencing golangci-lint usage or version.

References:

• golangci-lint v2 Migration Guide

Acceptance Criteria:

• CI passes with golangci-lint v2
• Documentation is updated
• No regressions in linting coverage or rules

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If any problems arise during migration, document workarounds or new required steps.