Tracking entry (detail in the package repo).

Control/Extend.lua used table.unpack (a Lua 5.2+ name; 5.1 has bare unpack) plus an off-by-one in arrayExtend — masked because the fork tested on Lua 5.3. Surfaced by pinning Lua 5.1 (the pslua target). Fixed together with the 5.1 pin in the alignment PR (coupled).

• Detail: Control/Extend.lua: table.unpack is Lua 5.2+ (undefined on 5.1), and arrayExtend is off-by-one purescript-lua-control#2
• Fix: chore: align build tooling (purescript-overlay, nix CI, Lua 5.1) purescript-lua-control#1 (bundled with the Lua-5.1 / overlay alignment)