Fix CI lint failure by preallocating parseSampleGroups result slice

[Copilot]

The CI lint job failed on main due to a prealloc violation in hack/gen-ai-docs/main.go. The failure was isolated to parseSampleGroups, where the output slice was appended without capacity preallocation.

• What changed

  • Updated parseSampleGroups to preallocate groups with len(kindOrder) before the append loop.
  • Removed the earlier zero-capacity declaration of groups.

• Why this addresses the issue

  • Aligns the function with golangci-lint’s prealloc requirement while preserving existing behavior and output order.

• Code change (excerpt)

// before
var groups []SampleGroup
for _, kind := range kindOrder {
    g := kindGroups[kind]
    g.Description = descriptions[kind]
    groups = append(groups, *g)
}

// after
groups := make([]SampleGroup, 0, len(kindOrder))
for _, kind := range kindOrder {
    g := kindGroups[kind]
    g.Description = descriptions[kind]
    groups = append(groups, *g)
}