feat: AI Act Decision Tree — Zwei-Achsen-Klassifikation (GPAI + High-Risk)

Interaktiver 12-Fragen-Entscheidungsbaum für die AI Act Klassifikation
auf zwei Achsen: High-Risk (Anhang III, Q1-Q7) und GPAI (Art. 51-56, Q8-Q12).
Deterministische Auswertung ohne LLM.

Backend (Go):
- Neue Structs: GPAIClassification, DecisionTreeAnswer, DecisionTreeResult
- Decision Tree Engine mit BuildDecisionTreeDefinition() und EvaluateDecisionTree()
- Store-Methoden für CRUD der Ergebnisse
- API-Endpoints: GET/POST /decision-tree, GET/DELETE /decision-tree/results
- 12 Unit Tests (alle bestanden)

Frontend (Next.js):
- DecisionTreeWizard: Wizard-UI mit Ja/Nein-Fragen, Dual-Progress-Bar, Ergebnis-Ansicht
- AI Act Page refactored: Tabs (Übersicht | Entscheidungsbaum | Ergebnisse)
- Proxy-Route für decision-tree Endpoints

Migration 083: ai_act_decision_tree_results Tabelle

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

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

@@ -1122,6 +1122,114 @@ func (h *UCCAHandlers) GetWizardSchema(c *gin.Context) {
 	})
 }
 
+// ============================================================================
+// AI Act Decision Tree Endpoints
+// ============================================================================
+
+// GetDecisionTree returns the decision tree structure for the frontend
+// GET /sdk/v1/ucca/decision-tree
+func (h *UCCAHandlers) GetDecisionTree(c *gin.Context) {
+	tree := ucca.BuildDecisionTreeDefinition()
+	c.JSON(http.StatusOK, tree)
+}
+
+// EvaluateDecisionTree evaluates the decision tree answers and stores the result
+// POST /sdk/v1/ucca/decision-tree/evaluate
+func (h *UCCAHandlers) EvaluateDecisionTree(c *gin.Context) {
+	tenantID := rbac.GetTenantID(c)
+	if tenantID == uuid.Nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "tenant ID required"})
+		return
+	}
+
+	var req ucca.DecisionTreeEvalRequest
+	if err := c.ShouldBindJSON(&req); err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+		return
+	}
+
+	if req.SystemName == "" {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "system_name is required"})
+		return
+	}
+
+	// Evaluate
+	result := ucca.EvaluateDecisionTree(&req)
+	result.TenantID = tenantID
+
+	// Parse optional project_id
+	if projectIDStr := c.Query("project_id"); projectIDStr != "" {
+		if pid, err := uuid.Parse(projectIDStr); err == nil {
+			result.ProjectID = &pid
+		}
+	}
+
+	// Store result
+	if err := h.store.CreateDecisionTreeResult(c.Request.Context(), result); err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		return
+	}
+
+	c.JSON(http.StatusCreated, result)
+}
+
+// ListDecisionTreeResults returns stored decision tree results for a tenant
+// GET /sdk/v1/ucca/decision-tree/results
+func (h *UCCAHandlers) ListDecisionTreeResults(c *gin.Context) {
+	tenantID := rbac.GetTenantID(c)
+	if tenantID == uuid.Nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "tenant ID required"})
+		return
+	}
+
+	results, err := h.store.ListDecisionTreeResults(c.Request.Context(), tenantID)
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		return
+	}
+
+	c.JSON(http.StatusOK, gin.H{"results": results, "total": len(results)})
+}
+
+// GetDecisionTreeResult returns a single decision tree result by ID
+// GET /sdk/v1/ucca/decision-tree/results/:id
+func (h *UCCAHandlers) GetDecisionTreeResult(c *gin.Context) {
+	id, err := uuid.Parse(c.Param("id"))
+	if err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "invalid ID"})
+		return
+	}
+
+	result, err := h.store.GetDecisionTreeResult(c.Request.Context(), id)
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		return
+	}
+	if result == nil {
+		c.JSON(http.StatusNotFound, gin.H{"error": "not found"})
+		return
+	}
+
+	c.JSON(http.StatusOK, result)
+}
+
+// DeleteDecisionTreeResult deletes a decision tree result
+// DELETE /sdk/v1/ucca/decision-tree/results/:id
+func (h *UCCAHandlers) DeleteDecisionTreeResult(c *gin.Context) {
+	id, err := uuid.Parse(c.Param("id"))
+	if err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "invalid ID"})
+		return
+	}
+
+	if err := h.store.DeleteDecisionTreeResult(c.Request.Context(), id); err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		return
+	}
+
+	c.JSON(http.StatusOK, gin.H{"message": "deleted"})
+}
+
 // ============================================================================
 // Helper functions
 // ============================================================================