docs: cookieless page-view counter and privacy page

SimLoop/docs/assets/javascripts/pageviews.js

@@ -0,0 +1,33 @@
+// Page-view counter for this docs site. Horizon (FTC 36596).
+//
+// It counts with GoatCounter, but runs no GoatCounter code: this file sends one image request to
+// GoatCounter's documented /count endpoint (goatcounter.com/help/pixel). No third-party script is
+// loaded on purpose: these pages share an origin with the other sites under
+// libraries.horizon36596.org, the Zenith web editor (/zenith/app/) among them, so a third-party
+// script here could read their browser storage.
+//
+// No cookies, no local storage. Sent: the page path and title, the referring page, and the screen
+// size. GoatCounter also sees the IP address and browser, as any web request does; it uses them to
+// work out the country and to count a reload once, keeps them in memory for at most 8 hours and does
+// not store them. The privacy page (privacy.md) says the same; change both together.
+//
+// Both docs sites (libraries.horizon36596.org/zenith/ and /simloop/) report to ONE GoatCounter site,
+// told apart by path. Until the owner creates that site, GOATCOUNTER_CODE is a placeholder and this
+// file does nothing.
+(function () {
+  var GOATCOUNTER_CODE = "REPLACE_WITH_GOATCOUNTER_CODE";
+  if (GOATCOUNTER_CODE.indexOf("REPLACE_") === 0) return;
+  // Local previews (mkdocs serve) are not counted.
+  if (location.hostname !== "libraries.horizon36596.org") return;
+  if (document.visibilityState === "prerender") return;
+  var q = [
+    "p=" + encodeURIComponent(location.pathname),
+    "t=" + encodeURIComponent(document.title),
+    "r=" + encodeURIComponent(document.referrer),
+    "s=" + [screen.width, screen.height, window.devicePixelRatio || 1].join(","),
+    "rnd=" + Math.random().toString(36).slice(2),
+  ];
+  // 153 is GoatCounter's "WebDriver-based headless browser" bot flag.
+  if (navigator.webdriver) q.push("b=153");
+  new Image().src = "https://" + GOATCOUNTER_CODE + ".goatcounter.com/count?" + q.join("&");
+})();

SimLoop/docs/privacy.md

@@ -0,0 +1,21 @@
+# Privacy
+
+SimLoop is a library. It has no analytics and collects nothing about you.
+
+This documentation site counts page views with [GoatCounter](https://www.goatcounter.com), so we can
+see which pages teams read.
+
+- It sets no cookies and stores nothing in your browser.
+- For each page view it records the page and its title, the site that linked you here, your
+  browser, operating system and screen size, and your country.
+- GoatCounter uses your IP address and browser to work out your country and to count a reload only
+  once. It keeps them in memory for at most 8 hours and never stores them.
+- No outside script runs on these pages. Our own page sends one request to GoatCounter; no
+  GoatCounter code is loaded.
+- It cannot tell who you are or follow you to other sites.
+
+The site is hosted on GitHub Pages, which keeps the routine request logs any website has, such as
+your IP address. Its fonts load from Google Fonts, which sees your IP address and browser the same
+way.
+
+Questions: open an issue on [GitHub](https://github.com/Horizon-36596/simloop/issues).

SimLoop/mkdocs.yml

@@ -83,8 +83,10 @@ extra_css:
   - stylesheets/horizon.css
 
 # The one-time alpha notice; its styles are at the end of horizon.css.
+# The cookieless page-view counter; see the file's header and privacy.md.
 extra_javascript:
   - javascripts/alpha-notice.js
+  - assets/javascripts/pageviews.js
 
 markdown_extensions:
   - admonition
@@ -133,3 +135,4 @@ nav:
       - Troubleshooting: troubleshooting.md
       - Reporting a bug: support.md
       - Index for AI agents: llms.md
+      - Privacy: privacy.md