feat(compliance): GET /sdk/v1/compliance/obligation-status (file-backed graph)

Vertical slice over the Compliance Execution Graph: obligation_id -> accepted
controls -> required evidence -> status. NEVER auto-asserts fulfillment - with
no evidence collection wired (MVP), a mapped obligation is "not_assessed" and
every required evidence is "missing". Fail-closed: no id -> 400; unknown id ->
unknown_obligation; mapped-but-no-control -> unmapped; graph not loaded -> 503.

- ComplianceGraphHandlers (separate from the DB-backed ObligationsHandlers):
  loads Registry join keys + accepted control mappings + evidence once at start.
- LoadComplianceGraph: candidate-path resolution across dev/container/test.
- Data plumbing: Dockerfile now COPYs data/{control_mappings,evidence_requirements,
  obligations}; data/obligations/obligation_join_keys.json is a SYNCED COPY of the
  repo-root Registry contract (re-sync on Registry growth).
- Table-driven handler test (mapped/unmapped/unknown/400 + no-fulfillment-claim).

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

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

@@ -0,0 +1,94 @@
+package handlers
+
+import (
+	"encoding/json"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/gin-gonic/gin"
+)
+
+func newComplianceGraphTestRouter(t *testing.T) *gin.Engine {
+	t.Helper()
+	gin.SetMode(gin.TestMode)
+	h := NewComplianceGraphHandlers()
+	if err := h.LoadError(); err != nil {
+		t.Fatalf("compliance graph failed to load (candidate paths): %v", err)
+	}
+	r := gin.New()
+	h.RegisterRoutes(r.Group("/sdk/v1"))
+	return r
+}
+
+func getObligationStatus(t *testing.T, r *gin.Engine, query string) (int, cgStatusResponse) {
+	t.Helper()
+	w := httptest.NewRecorder()
+	req, _ := http.NewRequest(http.MethodGet, "/sdk/v1/compliance/obligation-status"+query, nil)
+	r.ServeHTTP(w, req)
+	var resp cgStatusResponse
+	if w.Code == http.StatusOK {
+		if err := json.Unmarshal(w.Body.Bytes(), &resp); err != nil {
+			t.Fatalf("decode body %q: %v", w.Body.String(), err)
+		}
+	}
+	return w.Code, resp
+}
+
+func TestObligationStatus(t *testing.T) {
+	r := newComplianceGraphTestRouter(t)
+
+	tests := []struct {
+		name         string
+		query        string
+		wantHTTP     int
+		wantOverall  string
+		wantControls bool // expect >=1 control
+	}{
+		{"missing param -> 400", "", http.StatusBadRequest, "", false},
+		{"unknown id -> unknown_obligation", "?obligation_id=does_not_exist", http.StatusOK, "unknown_obligation", false},
+		{"mapped (OWASP V6) -> not_assessed", "?obligation_id=user_authentication_required", http.StatusOK, "not_assessed", true},
+		{"in registry, no control -> unmapped", "?obligation_id=sbom_creation", http.StatusOK, "unmapped", false},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			code, resp := getObligationStatus(t, r, tt.query)
+			if code != tt.wantHTTP {
+				t.Fatalf("http %d, want %d", code, tt.wantHTTP)
+			}
+			if tt.wantHTTP != http.StatusOK {
+				return
+			}
+			if resp.OverallStatus != tt.wantOverall {
+				t.Errorf("overall_status=%q, want %q", resp.OverallStatus, tt.wantOverall)
+			}
+			if tt.wantControls && len(resp.Controls) == 0 {
+				t.Error("expected >=1 control")
+			}
+			if !tt.wantControls && len(resp.Controls) != 0 {
+				t.Errorf("expected 0 controls, got %d", len(resp.Controls))
+			}
+			if resp.CitationSpans != "pending" {
+				t.Errorf("citation_spans=%q, want pending", resp.CitationSpans)
+			}
+		})
+	}
+}
+
+// The MVP must NEVER auto-assert fulfillment: with no evidence collection wired, every required
+// evidence is "missing" and the overall status stays "not_assessed".
+func TestObligationStatus_NoFulfillmentClaim(t *testing.T) {
+	r := newComplianceGraphTestRouter(t)
+	code, resp := getObligationStatus(t, r, "?obligation_id=user_authentication_required")
+	if code != http.StatusOK {
+		t.Fatalf("http %d", code)
+	}
+	if resp.OverallStatus == "met" || resp.OverallStatus == "erfuellt" {
+		t.Fatalf("MVP must not assert fulfillment, got overall_status=%q", resp.OverallStatus)
+	}
+	for _, ctl := range resp.Controls {
+		if len(ctl.EvidenceRequired) > 0 && ctl.EvidenceStatus != "missing" {
+			t.Errorf("control %s/%s evidence_status=%q, want missing (no collection wired)", ctl.Framework, ctl.Control, ctl.EvidenceStatus)
+		}
+	}
+}