Regex tooling: formula gene grouping, content patches, def validation

Three regex-powered content tools (phase G5):

- Formula group functions gsum/gcount/gavg/gmin/gmax('regex') aggregate
  over every context variable whose name matches the pattern, e.g.
  gsum('leaf_.*'). Adds string literals to the formula grammar and an
  IFormulaContext.ResolveMatching hook; GenomeContext enumerates matching
  genes, so a trait can sum/average a gene group.
- DefDatabase content patches: a { "type": "Patch", patches:[{ defType,
  match (regex on defName), set:{fields} }] } file sets fields on every
  matching raw def before resolution — mods patch Core in bulk.
- DefDatabase.RegisterValidator(typeKey, field, regex): load-time check
  that a string field matches a pattern, throwing otherwise (naming/format
  conventions).

Covered by FormulaTests (group aggregation, composition, bad calls) and
DefDatabaseTests (patch set/match/unknown-type, validator pass/reject).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/MrGameEng.Content/Genetics/Phenotype.cs

@@ -71,5 +71,17 @@ public static class Phenotype
 
             throw new FormulaException($"Unknown variable '{name}' while computing traits.");
         }
+
+        // Группировка генов в формулах: значения всех генов, чьи id подходят под шаблон (gsum/gavg/…).
+        public IEnumerable<float> ResolveMatching(Func<string, bool> matches)
+        {
+            foreach (var geneId in genome.Alleles.Keys)
+            {
+                if (matches(geneId) && registry.TryGetValue(geneId, out var gene))
+                {
+                    yield return genome.Express(gene);
+                }
+            }
+        }
     }
 }