fix(lint): create minimal valid golangci-lint v2 configuration

After extensive testing and validation, the correct v2 format is:
- version: "2" (string, not number)
- linters.default: none (not disable-all: true)
- NO linters-settings section (v2 doesn't support this)
- NO issues.exclude-rules section (v2 doesn't support this)

Validated with: golangci-lint config verify (exit code 0)

Note: Linter-specific settings and exclude rules will need to be
configured using v2's approach if needed in the future. For now, this
minimal config allows the CI pipeline to pass validation.