refactor: use slices and maps stdlib functions instead of manual implementations

[dgageot]

Replace manual loops and sort package usage with idiomatic Go stdlib functions from the slices and maps packages across 18 files:

• sort.Strings → slices.Sort
• sort.Slice → slices.SortFunc
• sort.SliceStable → slices.SortStableFunc
• append([]T(nil), src...) → slices.Clone
• Manual map-key collection → slices.Collect(maps.Keys(...))
• Manual map clone → maps.Clone
• Manual reverse loop → slices.Reverse
• Manual slice concat → slices.Concat
• Collect keys + sort → slices.Sorted(maps.Keys(...))

All changes are semantically equivalent to the original code. Linter passes, all unit tests pass.

[docker-agent]

Review Summary

Assessment: 🟢 APPROVE

This PR successfully refactors manual loop implementations to use idiomatic Go stdlib functions from the slices and maps packages. The changes are semantically equivalent to the original code with no bugs detected.

Key Changes Verified:

• ✅ sort.Strings → slices.Sort (3 files)
• ✅ sort.Slice → slices.SortFunc (5 files)
• ✅ sort.SliceStable → slices.SortStableFunc (1 file)
• ✅ append([]T(nil), src...) → slices.Clone (6 files)
• ✅ Manual map-key collection → slices.Collect(maps.Keys(...)) (3 files)
• ✅ Manual map clone → maps.Clone (1 file)
• ✅ Manual reverse loop → slices.Reverse (1 file)
• ✅ Manual slice concat → slices.Concat (2 files)
• ✅ Collect keys + sort → slices.Sorted(maps.Keys(...)) (1 file)

All comparison functions in slices.SortFunc and slices.SortStableFunc use the correct cmp.Compare logic that maintains the original sort order semantics. No behavioral changes, nil handling issues, or off-by-one errors detected.

The refactoring improves code readability and aligns with modern Go idioms (Go 1.21+).