feat(reporting+docs): tenant-ID-Validierung, Go-Tests, 4 MkDocs-Einzelseiten

- reporting_handlers.go: uuid.Nil-Check vor Store-Aufruf (→ 400)
- reporting_handlers_test.go: 4 MissingTenantID-Tests (PASS) + 4 WithTenant-Tests (SKIP)
- docs-src: requirements.md, controls.md, evidence.md, risks.md (je mit API, Schema, Tests)
- mkdocs.yml: 4 neue Nav-Einträge + \n-Bug auf Zeile 91 behoben
- compliance-kern.md: Link-Hinweise zu Detailseiten ergänzt

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

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

@@ -6,6 +6,7 @@ import (
 	"github.com/breakpilot/ai-compliance-sdk/internal/rbac"
 	"github.com/breakpilot/ai-compliance-sdk/internal/reporting"
 	"github.com/gin-gonic/gin"
+	"github.com/google/uuid"
 )
 
 type ReportingHandlers struct {
@@ -20,6 +21,10 @@ func NewReportingHandlers(store *reporting.Store) *ReportingHandlers {
 // GET /sdk/v1/reporting/executive
 func (h *ReportingHandlers) GetExecutiveReport(c *gin.Context) {
 	tenantID := rbac.GetTenantID(c)
+	if tenantID == uuid.Nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "tenant ID required"})
+		return
+	}
 
 	report, err := h.store.GenerateReport(c.Request.Context(), tenantID)
 	if err != nil {
@@ -34,6 +39,10 @@ func (h *ReportingHandlers) GetExecutiveReport(c *gin.Context) {
 // GET /sdk/v1/reporting/score
 func (h *ReportingHandlers) GetComplianceScore(c *gin.Context) {
 	tenantID := rbac.GetTenantID(c)
+	if tenantID == uuid.Nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "tenant ID required"})
+		return
+	}
 
 	report, err := h.store.GenerateReport(c.Request.Context(), tenantID)
 	if err != nil {
@@ -52,6 +61,10 @@ func (h *ReportingHandlers) GetComplianceScore(c *gin.Context) {
 // GET /sdk/v1/reporting/deadlines
 func (h *ReportingHandlers) GetUpcomingDeadlines(c *gin.Context) {
 	tenantID := rbac.GetTenantID(c)
+	if tenantID == uuid.Nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "tenant ID required"})
+		return
+	}
 
 	report, err := h.store.GenerateReport(c.Request.Context(), tenantID)
 	if err != nil {
@@ -69,6 +82,10 @@ func (h *ReportingHandlers) GetUpcomingDeadlines(c *gin.Context) {
 // GET /sdk/v1/reporting/risks
 func (h *ReportingHandlers) GetRiskOverview(c *gin.Context) {
 	tenantID := rbac.GetTenantID(c)
+	if tenantID == uuid.Nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "tenant ID required"})
+		return
+	}
 
 	report, err := h.store.GenerateReport(c.Request.Context(), tenantID)
 	if err != nil {