Extract Files seam, WebDAV, and Visit from CheckDNS.

Publish go-nc-files v1 with local/WebDAV Root, DefaultPathStore, and
neutral Working Folder language; depends on go-nc-exapp v0.1.0.

Co-authored-by: Cursor <cursoragent@cursor.com>

errors.go

@@ -0,0 +1,13 @@
+package goncfiles
+
+import "errors"
+
+// IsNotExist reports whether err wraps ErrNotExist.
+func IsNotExist(err error) bool {
+	return errors.Is(err, ErrNotExist)
+}
+
+// IsForbidden reports whether err wraps ErrForbidden.
+func IsForbidden(err error) bool {
+	return errors.Is(err, ErrForbidden)
+}