docs: record authorship and how to credit it

Credit is not a courtesy here, it is a factual claim about who decided
what. Christian supplied the question, the framing (the browser is the top
layer of the OS), and the field evidence; the code and its failures are
mine. AUTHORS.md states that split so a future reader does not have to
guess.

Co-developed-with: CLU <clu@binaryranch.com>

AUTHORS.md

@@ -0,0 +1,28 @@
+# Authorship
+
+Vitals was built by two parties, and the split is not decorative.
+
+**Christian Sass** — product direction and requirements. The question that
+started it ("why are all my CPUs pegged, and why is this process manager
+useless at telling me?") is his. So is the framing that gave the tool its shape:
+the browser is the top layer of the operating system, so a process monitor that
+stops at the browser boundary is measuring the wrong thing. He supplied the field
+evidence, including the ten leaked headless browser instances that made the
+failure mode concrete, and he made every product call about what belongs on the
+screen and what does not.
+
+**CLU** (Codified Likeness Utility, Binary Ranch) — architecture and
+implementation. Identity resolution, the CDP client and the tab-to-process join,
+the sampler, the UI, the tests, the demo mode, and this documentation.
+
+Both parties reviewed the result together against live machine data. Where the
+code is wrong, it is CLU's error. Where the tool is pointed at the wrong
+question, it is Christian's.
+
+## Attribution
+
+If you cite or fork this work, credit both: "Vitals, Christian Sass and CLU
+(Binary Ranch)". Commits carry a `Co-developed-with` trailer for the same
+reason.
+
+Contact: csass@binaryranch.com

README.md

@@ -150,6 +150,13 @@ coarse by design.
 - a second adapter for non-Chromium browsers through their own remote protocols
 - macOS and BSD sampling backends, same model
 
+## Authorship
+
+Built by Christian Sass (product direction, requirements, and the observation
+that the browser is the top layer of the operating system) and CLU (architecture
+and implementation). Details in [AUTHORS.md](AUTHORS.md). Commits carry a
+`Co-developed-with` trailer.
+
 ## License
 
 MIT. See [LICENSE](LICENSE).