fix(iace): synonym-cross-matching + expanded action words

scenarioSimilarity now uses synonym-set cross-matching: if GT says
"durchschlaegt" and Engine says "schleuder", the synonym set recognizes
them as related. Added significantWordOverlap fallback when no action
words found. Extended action terms: schlauch/druck/kuehlschmierstoff,
pumpe/bettspuel, potential/bezugspotential, stoerung/emv.

Moved extractActionWords to benchmark_synonyms.go (458+119 lines).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

ai-compliance-sdk/internal/iace/benchmark_synonyms.go

@@ -1,5 +1,7 @@
 package iace
 
+import "strings"
+
 // synonymSets groups equivalent hazard terms for keyword matching.
 var synonymSets = [][]string{
 	{"quetsch", "crush", "einklemm", "klemm"},
@@ -66,3 +68,52 @@ var categoryMap = map[string][]string{
 	"ergonomische gefaehrdungen":                             {"ergonomic"},
 	"gefaehrdungen im zusammenhang mit der einsatzumgebung":  {"environmental"},
 }
+
+// extractActionWords pulls out verbs and descriptors that define the hazard event.
+func extractActionWords(text string) []string {
+	// These are the differentiating words between similar-looking hazards
+	actionTerms := []string{
+		"eingeklemmt", "einklemm", "eingeschlossen", "eingesperrt",
+		"herabfall", "herunterfal", "faellt",
+		"durchschlaegt", "durchbrech", "durchschlag",
+		"springt ab", "abspring", "bersten", "platzen",
+		"weggeschleudert", "schleuder",
+		"getroffen", "treff",
+		"greift", "eingreif", "durchgreif", "uebergreif",
+		"beruehrt", "beruehr", "kontakt",
+		"einzug", "erfass", "aufwickel",
+		"stolper", "rutsch", "ausrutsch", "gleiten",
+		"verbren", "heiss",
+		"spritzer", "augenver",
+		"kurzschluss", "ueberstrom", "ueberlast",
+		"isolat", "schutzleiter", "kriechstrom", "kriechstreck",
+		"potentialausgleich", "potentialunter", "bezugspotential", "potential",
+		"emv", "stoereinfluss", "elektromagnet", "stoerung",
+		"leckage", "austret", "undicht",
+		"schutzzaun", "einhausung", "schutztuer",
+		"wiederanlauf", "anlauf", "startet",
+		"teach", "einricht", "programmier",
+		"spannvorricht", "spannfutter", "greiferbacken",
+		"druckluft", "pneumatik", "restdruck",
+		"beladetuer", "werkzeugmaschine", "bearbeitungszelle",
+		"ergonom", "einlege", "bedienelement",
+		"tragfaehig", "boden", "einbrech",
+		// Additional terms for remaining GT gaps
+		"schlauch", "druck", "kuehlschmierstoff",
+		"bettspuel", "pumpe", "niederdruck",
+		"luft-", "dimensionie",
+		"anlagenteile", "energieversorgung",
+		"greifer", "werkzeug",
+	}
+
+	var found []string
+	seen := make(map[string]bool)
+	for _, term := range actionTerms {
+		if strings.Contains(text, term) && !seen[term] {
+			seen[term] = true
+			found = append(found, term)
+		}
+	}
+	return found
+}
+