docs: add README.org for repl, tangle, org-eval, verify-repl tools

projects/tangle-tool/README.org

@@ -0,0 +1,16 @@
+#+TITLE: tangle
+
+Generate .lisp files from .org sources via Emacs org-babel-tangle.
+
+== Usage
+
+#+begin_src shell
+  tangle org/file.org
+#+end_src
+
+Requires the org file to have ~#+PROPERTY: header-args:lisp :tangle target.lisp~
+or per-block ~:tangle~ headers. Files without a ~:tangle~ header are skipped.
+
+== Dependencies
+
+Emacs with org-mode (ob-tangle).