rugnux: show the space-group search on rotation data

The search runs in pass 1 of the rotation two-pass; pass 2 only reuses the
group it decided, so the result the CLI renders carried no search at all
and the whole report - operator correlations, the space-group candidate
table, the refused higher symmetry - was silently dropped on every
rotation dataset. Most costly of all, the "or <group> (indistinguishable
from these data)" line never appeared, so an enantiomorphic pair the
intensities genuinely cannot separate was reported as a single answer.
Carry pass 1's search into the returned result.

Also de-duplicate the alternatives when the centred-lattice test swaps the
metric-matching candidate into the answer: the group it displaced was left
out and the chosen one listed twice ("C2 or P21 or C2").

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

rugnux/Rugnux.cpp

@@ -286,6 +286,11 @@ ProcessResult Rugnux::Run(RugnuxObserver *observer) {
                 force_rotation_result_.reset();
             }
         }
+        // The space group was DECIDED in pass 1 and only reused by pass 2, which therefore has no search
+        // of its own to report. Carry pass 1's over, or the evidence behind the decision (operator CCs,
+        // absence counts, the refused higher symmetry) is never shown on the default rotation path.
+        if (!pass2.space_group_search.has_value())
+            pass2.space_group_search = pass1.space_group_search;
         return pass2;
     }
     return RunPipeline(observer, /*write_output=*/true, /*geometry_prepass=*/false);
@@ -1351,6 +1356,15 @@ ProcessResult Rugnux::RunPipeline(RugnuxObserver *observer, bool write_output, b
                         // cell we reindex into - otherwise the space group and the written cell disagree.
                         if (chosen.centring_type() == cand.centering) {
                             sg_search = s2;
+                            // Swap the metric-matching candidate into the answer and leave the one it
+                            // displaced among the alternatives, so the reported "or ..." list stays the
+                            // set of groups the data cannot separate, each named once.
+                            if (chosen.number != s2.best_space_group->number) {
+                                sg_search.alternatives.push_back(*s2.best_space_group);
+                                std::erase_if(sg_search.alternatives, [&](const gemmi::SpaceGroup &a) {
+                                    return a.number == chosen.number;
+                                });
+                            }
                             sg_search.best_space_group = chosen;
                             commit_reindex = reindex;
                             commit_cell = cand.conventional.GetUnitCell();