[kevin9327]

Problem

capacityToNumber (used to sort capacity columns) calls resource.MustParse, which panics on any value that isn't a Kubernetes quantity. #3869 handled the empty string, but other non-quantity values still crash k9s when that column is sorted:

• A custom column with the N attribute (|N sets Capacity: true) shows n/a whenever its JSONPath finds nothing (cust_cols.go sets v = NAValue). Sorting by that column takes down k9s with
  panic: cannot parse 'n/a': quantities must match the regular expression ...
• The same happens with <none> or text values such as 1/3 in an N column.

Fix

Use resource.ParseQuantity instead. A value that doesn't parse returns math.MaxInt64, so placeholders sort last, the same way durationToSeconds already handles <unknown>, <none> and n/a in age columns.

Tests

I added n/a, <none> and 1/3 cases to TestCapacityToNumber. Before the fix the test panics; after it, go test ./internal/model1 passes.

This PR was prepared with AI assistance. I reviewed and tested the change myself.

[uozalp]

@kevin9327 thanks for this update