test: Add edge case tests for auth helper functions

- respondMissingScope: nil writer handling (80% to 100%)
- attachAPITokenRecord: nil record handling (80% to 100%)
- getAPITokenRecordFromRequest: wrong type and missing value (87.5% to 100%)

internal/api/auth_scope_test.go

@@ -1,6 +1,7 @@
 package api
 
 import (
+	"context"
 	"net/http"
 	"net/http/httptest"
 	"testing"
@@ -56,3 +57,46 @@ func TestRequireScopeAllowsMatchingScope(t *testing.T) {
 		t.Fatalf("expected status 202 when scope present, got %d", rr.Code)
 	}
 }
+
+func TestRespondMissingScopeNilWriter(t *testing.T) {
+	// Should not panic when called with nil writer
+	respondMissingScope(nil, "some-scope")
+}
+
+func TestAttachAPITokenRecordNilRecord(t *testing.T) {
+	req := httptest.NewRequest(http.MethodGet, "/", nil)
+	originalCtx := req.Context()
+
+	// Should not panic and should not modify context when record is nil
+	attachAPITokenRecord(req, nil)
+
+	// Context should remain unchanged
+	if req.Context() != originalCtx {
+		t.Fatal("context should not change when attaching nil record")
+	}
+}
+
+func TestGetAPITokenRecordFromRequestWrongType(t *testing.T) {
+	req := httptest.NewRequest(http.MethodGet, "/", nil)
+
+	// Attach a value of wrong type to the context
+	ctx := req.Context()
+	ctx = context.WithValue(ctx, contextKeyAPIToken, "not-a-record")
+	req = req.WithContext(ctx)
+
+	// Should return nil when type assertion fails
+	record := getAPITokenRecordFromRequest(req)
+	if record != nil {
+		t.Fatal("expected nil when context value is wrong type")
+	}
+}
+
+func TestGetAPITokenRecordFromRequestNoValue(t *testing.T) {
+	req := httptest.NewRequest(http.MethodGet, "/", nil)
+
+	// No token attached - should return nil
+	record := getAPITokenRecordFromRequest(req)
+	if record != nil {
+		t.Fatal("expected nil when no token in context")
+	}
+}