Do not require the SmallGrp package

[fingolfin]

Viewing or displaying an rcwa group fails when the SmallGrp package is not loaded:

gap> G := Group(ClassTransposition(0,2,1,2));
<rcwa group over Z with
1 generatorError, Variable: 'HasIdGroup' must have an assigned value

The ViewObj and Display methods in lib/rcwagrp.gi mention the isomorphism type of a group if IdGroup happens to be known, but both that attribute and its tester HasIdGroup are provided by SmallGrp.

Since only SmallGrp can set the attribute, it is certainly not set when the package is absent, so treating it as unset in that case is safe. This adds two helpers, RCWA_HasIdGroup and RCWA_IdGroup, and uses them in the two places concerned. Output is unchanged when SmallGrp is available, and falls back to printing the order otherwise.

Note the helpers deliberately go through ValueGlobal: writing HasIdGroup(G) textually — even behind a working IsBound guard — still makes GAP emit Syntax warning: Unbound global variable while reading the file. With this change RCWA loads without any such warnings.

Four tests in tst/integral.tst also needed SmallGrp: two call IdGroup directly, and two use StructureDescription, which yields prettier names when it can consult NAMES_OF_SMALL_GROUPS. These are guarded with the #@if syntax of the test file parser. For the IdGroup case there is an #@else branch, so the new fallback output is covered too.

Testing

• gap --bare -c 'LoadPackage("GAPDoc");' + LoadPackage("rcwa" : OnlyNeeded) + TestPackage("rcwa") — 0 failures in 14 files, and no syntax warnings. Previously 58 differences.
• Normal run with full package autoload — 0 failures in 14 files, output unchanged.

I have left PackageInfo.g and the release date in CHANGES.md alone, so this needs a version bump and release on your side.

Context

This comes out of gap-system/gap#2434, which aims to make GAP and its packages work when PrimGrp/SmallGrp/TransGrp are not installed. RCWA showed up in a PackageDistro CI experiment running package test suites under gap --bare.

🤖 Generated with Claude Code

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 99.58%. Comparing base (dbedaff) to head (74d98a8).

Additional details and impacted files

@@           Coverage Diff           @@
##           master      #34   +/-   ##
=======================================
  Coverage   99.58%   99.58%           
=======================================
  Files          47       47           
  Lines      366226   366230    +4     
=======================================
+ Hits       364707   364711    +4     
  Misses       1519     1519           

Files with missing lines	Coverage Δ
lib/rcwagrp.gi	84.05% <100.00%> (+0.01%)	⬆️

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[fingolfin]

@Stefan-Kohl are you OK with these changes, and putting them into a release? happy to answer questions

[Stefan-Kohl]

@fingolfin Thanks - the changes are fine with me. I have made a release.