feat(iace): Sprint 4D — Failure Mode Layer (FMEA-Faehigkeit)

150 Failure Modes in 11 ComponentTypes:
- Sensor (20): Signalverlust, Drift, Falschmeldung, Encoder-spezifisch
- Controller (20): Watchdog, Speicher, Bus, Safety-SPS CCF, Antrieb
- Actuator (15): Blockiert, Ueberlast, Haltekraftverlust, Schuetz verschweisst
- Mechanical (20): Ermuedungsbruch, Lagerschaden, Kettenriss, Werkzeugbruch
- Electrical (15): Isolation, Kurzschluss, Erdschluss, Lichtbogen
- Software (15): Exception, Race Condition, Buffer Overflow, Timing
- Hydraulic/Pneumatic (15): Schlauchplatzer, Ventil blockiert, Kavitation
- Safety Device (15): Failure-to-trip, CCF, Bremsenverschleiss, PL-Degradation
- Network (10): Paketverlust, Latenz, Man-in-the-Middle
- AI/ML (5): Model Drift, Adversarial Input, Bias

Architektur:
- FailureModeEntry Struct mit FMEA-Scores (Severity/Occurrence/Detection 1-10)
- RPZ = S x O x D (max 1000, Schwelle >= 100 = Massnahme erforderlich)
- RequiredFailureModes auf HazardPattern fuer FM-gesteuertes Pattern-Matching
- MatchInput.FailureModes + MatchReason "failure_mode" (Explainability)
- GET /failure-modes?component_type= API-Endpoint

10 Tests: Count, UniqueIDs, ValidTypes, NonEmpty, Distribution, RPZ (3x), NilFires, RPZDistribution

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

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

@@ -88,6 +88,33 @@ func DeriveHazardType(h *Hazard) string {
 	return DefaultHazardType
 }
 
+// FailureModeEntry represents a potential failure mode for a component type.
+// Used for FMEA (Failure Mode and Effects Analysis) — the chain is:
+// Component → FailureMode → HazardousSituation → Harm.
+type FailureModeEntry struct {
+	ID            string `json:"id"`             // e.g. "FM-SEN-01"
+	ComponentType string `json:"component_type"` // e.g. "sensor", "controller"
+	Mode          string `json:"mode"`           // e.g. "loss_of_signal", "drift"
+	NameDE        string `json:"name_de"`
+	NameEN        string `json:"name_en"`
+	Effect        string `json:"effect"`          // System-level effect
+	DetectionHint string `json:"detection_hint"`  // How to detect this failure
+	// FMEA scores (each 1-10)
+	DefaultSeverity   int `json:"default_severity"`   // Impact severity
+	DefaultOccurrence int `json:"default_occurrence"`  // How often it occurs
+	DefaultDetection  int `json:"default_detection"`   // Detectability (10=undetectable, 1=immediately detectable)
+}
+
+// CalculateRPZ computes the Risk Priority Number for a failure mode.
+// RPZ = Severity × Occurrence × Detection. Range: 1-1000.
+// RPZ > 100: action required. RPZ > 200: critical.
+func (fm *FailureModeEntry) CalculateRPZ() int {
+	return fm.DefaultSeverity * fm.DefaultOccurrence * fm.DefaultDetection
+}
+
+// RPZThresholdAction is the RPZ value above which corrective action is required.
+const RPZThresholdAction = 100
+
 // AssessmentType represents the type of risk assessment
 type AssessmentType string