Perform full Go 1.26 modernization sweep #39
Description
Problem
A full modernization sweep is needed to adopt safe Go 1.26 idioms and cleanup opportunities across the whole repository.
Expected Outcome
- Review all Go source and test files for safe Go 1.26 modernization opportunities.
- Apply automatic rewrites where applicable, plus manual idiomatic refactors that do not change behavior.
- Preserve public API compatibility.
- Validate equivalence with full build/vet/test gates and compare performance against the established benchmark baseline.
Acceptance Criteria
go build ./...,go vet ./...,go test ./...all pass.- No intentional public API changes.
- Changes are scoped to modernization/cleanup only (no feature work mixed in).
- Benchmark delta is documented against the baseline (or explicitly "no significant change").