Fix unresolved review issues in WidthStrategy implementations

[apstndb]

Summary

Address two unresolved review comments from #569 (merged) that were identified after merge.

Issues

1. GreedyFrequencyStrategy: potential panic on short rows

File: internal/mycli/format/width_strategy_greedy.go:54

lo.Must(lo.Nth(in, columnIdx)) will panic if a row has fewer columns than len(headers). The other strategies (ProportionalStrategy, MarginalCostStrategy) already have bounds checks. The fix is to add a similar guard:

func(in Row) string {
    if columnIdx < len(in) {
        return in[columnIdx].RawText()
    }
    return ""
},

2. ProportionalStrategy: remaining width not distributed when totalDeficit == 0

File: internal/mycli/format/width_strategy_proportional.go:95

When the initial header-based allocation already covers the natural width of all columns (totalDeficit == 0), the remaining width is not distributed at all, resulting in a table narrower than available screen width. The fix is to restructure the distribution block so that leftover is always assigned even when totalDeficit == 0.

References

• PR: feat(format): add WidthStrategy interface for pluggable column width algorithms #569
• Greedy panic review thread
• Proportional totalDeficit review thread

Scope

• Add bounds check in GreedyFrequencyStrategy.CalculateWidths()
• Fix ProportionalStrategy to distribute remaining width when totalDeficit == 0
• Add test cases for both edge cases