feat(iace): VDA-Format FMEA Excel Export

- GET /projects/:id/fmea/export → xlsx im VDA-Formblatt
- Spalten: Nr, Komponente, Typ, Fehlerart, Fehlerfolge, S, O, D, RPZ, AP, Massnahme
- AP-Zellen farbig: H=rot, M=gelb, L=gruen
- Dependency: github.com/xuri/excelize/v2 (BSD-3-Clause)
- Frontend: "VDA Excel exportieren" Button auf FMEA-Seite

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

ai-compliance-sdk/internal/api/handlers/iace_handler_fmea.go

@@ -0,0 +1,81 @@
+package handlers
+
+import (
+	"fmt"
+	"net/http"
+
+	"github.com/breakpilot/ai-compliance-sdk/internal/iace"
+	"github.com/gin-gonic/gin"
+	"github.com/google/uuid"
+)
+
+// ExportFMEA handles GET /projects/:id/fmea/export
+// Returns an xlsx file in VDA FMEA format.
+func (h *IACEHandler) ExportFMEA(c *gin.Context) {
+	projectID, err := uuid.Parse(c.Param("id"))
+	if err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "invalid project ID"})
+		return
+	}
+
+	ctx := c.Request.Context()
+	project, err := h.store.GetProject(ctx, projectID)
+	if err != nil || project == nil {
+		c.JSON(http.StatusNotFound, gin.H{"error": "project not found"})
+		return
+	}
+
+	// Load components
+	components, _ := h.store.ListComponents(ctx, projectID)
+
+	// Load all failure modes
+	allFMs := iace.GetFailureModeLibrary()
+
+	// Build FMEA rows: each component × matching FMs
+	var rows []iace.FMEAExportRow
+	for _, comp := range components {
+		compType := string(comp.ComponentType)
+		var compFMs []iace.FailureModeEntry
+		for _, fm := range allFMs {
+			if fm.ComponentType == compType {
+				compFMs = append(compFMs, fm)
+			}
+		}
+		if len(compFMs) == 0 {
+			// Fallback: mechanical FMs
+			for _, fm := range allFMs {
+				if fm.ComponentType == "mechanical" && len(compFMs) < 3 {
+					compFMs = append(compFMs, fm)
+				}
+			}
+		}
+
+		for _, fm := range compFMs {
+			s, o, d := fm.DefaultSeverity, fm.DefaultOccurrence, fm.DefaultDetection
+			rows = append(rows, iace.FMEAExportRow{
+				ComponentName: comp.Name,
+				ComponentType: compType,
+				FailureMode:   fm.NameDE,
+				FailureEffect: fm.Effect,
+				FailureCause:  fm.DetectionHint,
+				Severity:      s,
+				Occurrence:    o,
+				Detection:     d,
+				RPZ:           s * o * d,
+				AP:            iace.CalculateAP(s, o, d),
+				Measure:       "",
+				DetectionHint: fm.DetectionHint,
+			})
+		}
+	}
+
+	xlsxBytes, err := iace.GenerateFMEAExcel(project.MachineName, rows)
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": fmt.Sprintf("Excel generation failed: %v", err)})
+		return
+	}
+
+	filename := fmt.Sprintf("FMEA-%s.xlsx", project.MachineName)
+	c.Header("Content-Disposition", fmt.Sprintf("attachment; filename=\"%s\"", filename))
+	c.Data(http.StatusOK, "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet", xlsxBytes)
+}