feat(suitbuilder): CD-tier filter helpers + tests; gate inventory-go build on go test

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

go-services/inventory-go/suit_cd.go

@@ -0,0 +1,74 @@
+package main
+
+import "strings"
+
+// CD-tier filtering for the suitbuilder. The allowed_crit_damage constraint
+// restricts which crit-damage tiers are permitted on ARMOR pieces; jewelry and
+// clothing are never affected. "Prefer the highest allowed tier" is NOT done
+// here — it falls out of the existing scoring (CritDamage2 > CritDamage1) and
+// the CD-descending armor sort once disallowed tiers are removed.
+
+// critTier normalizes a raw crit_damage_rating into a tier in {0,1,2}. Rare
+// high-crit gear (rating >= 2, including 3+) collapses to tier 2 so it counts
+// as "CD2" rather than being silently excluded.
+func critTier(rating int) int {
+	switch {
+	case rating <= 0:
+		return 0
+	case rating == 1:
+		return 1
+	default:
+		return 2
+	}
+}
+
+// isArmorSlot reports whether a slot name denotes an armor coverage slot,
+// including comma-joined multi-coverage slots like "Chest, Abdomen".
+func isArmorSlot(slot string) bool {
+	if armorSlotSet[slot] {
+		return true
+	}
+	if strings.Contains(slot, ", ") {
+		for _, p := range strings.Split(slot, ", ") {
+			if armorSlotSet[strings.TrimSpace(p)] {
+				return true
+			}
+		}
+	}
+	return false
+}
+
+// allowedCritSet normalizes the constraint's allowed crit-damage tiers into a
+// set, or returns nil when the filter is INACTIVE: no values, or all three
+// tiers {0,1,2} present (== default). A nil result means "no filter" and keeps
+// the default search path byte-identical to the unfiltered solver.
+func allowedCritSet(vals []int) map[int]bool {
+	if len(vals) == 0 {
+		return nil
+	}
+	set := map[int]bool{}
+	for _, v := range vals {
+		set[critTier(v)] = true
+	}
+	if set[0] && set[1] && set[2] {
+		return nil
+	}
+	return set
+}
+
+// filterArmorByCD drops armor items whose crit-damage tier is not in allowed.
+// Non-armor items (jewelry, clothing, unknown) always pass through. When
+// allowed is nil the input is returned unchanged.
+func filterArmorByCD(items []*SuitItem, allowed map[int]bool) []*SuitItem {
+	if allowed == nil {
+		return items
+	}
+	out := make([]*SuitItem, 0, len(items))
+	for _, it := range items {
+		if isArmorSlot(it.Slot) && !allowed[critTier(it.Ratings["crit_damage_rating"])] {
+			continue
+		}
+		out = append(out, it)
+	}
+	return out
+}