* Fix fragment exports for older Xray clients
* fix(link): tolerate a finalmask without tcp in panel share links
withLegacyFragmentRanges called finalmask.tcp.map unguarded, but stored
rows reach the link generator unparsed and dropEmptyFinalMask deletes an
empty tcp list on save. Any VMess/VLESS/Trojan/SS inbound with only UDP
masks or quicParams threw a TypeError in the QR, info and export-links
views. The Go counterpart already skipped a missing tcp.
Also trims the Go helper's comment to the two-line cap and drops a
[]string branch no JSON-decoded finalmask can reach.
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Co-authored-by: Artem K <[email protected]>
Co-authored-by: Sanaei <[email protected]>