docs(website): add cookieless Umami analytics + a privacy page

Wire self-hosted Umami (umami.oliversturm.com) into the site head:
- data-domains=relplay.org so the preview/staging deploys don't pollute
  the production stats
- data-do-not-track so DNT visitors aren't counted
- the Website ID is public by design (ships in every page)

Add a short /privacy page (footer-linked, kept out of the sidebar)
explaining the no-cookies / no-personal-data / no-cross-site-tracking
posture and the DNT behaviour. No cookie banner is needed: the tracker
stores nothing on the device, and first-party statistical analytics is
exempt from PECR consent under the Data (Use and Access) Act 2025.

website/astro.config.mjs

@@ -58,6 +58,25 @@ export default defineConfig({
 				},
 				{ tag: 'meta', attrs: { name: 'twitter:card', content: 'summary_large_image' } },
 				{ tag: 'meta', attrs: { name: 'twitter:image', content: 'https://relplay.org/og-card.png' } },
+				// Privacy-friendly, cookieless analytics (self-hosted Umami). The
+				// Website ID is public by design (it ships in every page). The script
+				// loads from the Umami host, which also becomes the data destination,
+				// so no `data-host-url` is needed.
+				//   - data-domains: only run on the production apex, so the
+				//     `website.relplay.pages.dev` preview and `staging.relplay.org`
+				//     don't pollute the stats.
+				//   - data-do-not-track: honour the browser's Do-Not-Track signal
+				//     (those visits are not counted at all). See /privacy.
+				{
+					tag: 'script',
+					attrs: {
+						defer: true,
+						src: 'https://umami.oliversturm.com/script.js',
+						'data-website-id': 'fd77cfa5-cffe-4fc8-addb-1c6d7b6d9939',
+						'data-domains': 'relplay.org',
+						'data-do-not-track': true,
+					},
+				},
 			],
 			// Register the simple-mode command grammar with Expressive Code (Shiki).
 			expressiveCode: { shiki: { langs: [rdbmsLang, rdbmsSyntax] } },

website/src/components/Footer.astro

@@ -15,6 +15,8 @@ import Default from '@astrojs/starlight/components/Footer.astro';
 		Made by <a href="https://www.lazyevaluation.biz/">Lazy Evaluation Ltd</a>
 		<span class="sep">·</span>
 		<a href="https://git.lazyeval.net/oli/rdbms-playground">Source &amp; issues</a>
+		<span class="sep">·</span>
+		<a href="/privacy/">Privacy</a>
 	</p>
 </div>
 

website/src/components/InstallOsDetect.astro

@@ -0,0 +1,39 @@
+---
+// Pre-selects the install-instructions tab that matches the visitor's OS.
+//
+// This piggybacks on Starlight's synced-tabs mechanism rather than fighting it.
+// A `<Tabs syncKey="install-os">` restores its active tab from
+// `localStorage["starlight-synced-tabs__install-os"]` via a script Starlight
+// inlines *before* the tabs render (so there is no flash of the wrong tab). All
+// we do here is seed that same key with the detected OS — and only when the
+// visitor has not already chosen a tab themselves, so a manual choice always wins.
+//
+// Requirements (mirrors Starlight's own restore script):
+//   - Must be placed *before* the `<Tabs>` it targets, so this runs first.
+//   - The stored value must equal one of the TabItem labels exactly
+//     ("Linux" / "macOS" / "Windows").
+//   - Inlined, so it runs during parse before the restore script's
+//     connectedCallback and paint.
+---
+
+<script is:inline>
+	(() => {
+		const KEY = 'starlight-synced-tabs__install-os';
+		try {
+			// A previously stored value is a deliberate user choice — never override it.
+			if (localStorage.getItem(KEY)) return;
+			const data = navigator.userAgentData;
+			const platform = ((data && data.platform) || navigator.platform || '').toLowerCase();
+			const ua = (navigator.userAgent || '').toLowerCase();
+			let os = null;
+			if (platform.includes('win') || ua.includes('windows')) os = 'Windows';
+			else if (platform.includes('mac') || ua.includes('mac os x')) os = 'macOS';
+			else if (platform.includes('linux') || platform.includes('x11') || ua.includes('linux'))
+				os = 'Linux';
+			if (os) localStorage.setItem(KEY, os);
+		} catch (e) {
+			// localStorage unavailable (private mode, blocked cookies, …) — silently
+			// fall back to the default first tab. No detection, no harm.
+		}
+	})();
+</script>

website/src/content/docs/getting-started/installation.mdx

@@ -5,77 +5,105 @@ sidebar:
   order: 1
 ---
 
+import { Tabs, TabItem } from '@astrojs/starlight/components';
+import InstallOsDetect from '../../../components/InstallOsDetect.astro';
+
 RDBMS Playground is a single self-contained program. There is nothing to
 configure and no separate database to install — everything it needs is
 built in.
 
-Pick whichever method suits your platform. The one-line installers are the
+Pick the tab for your platform — we try to select it automatically — then
-quickest if you just want to get going.
+use whichever method you prefer. The one-line installers are the quickest if
+you just want to get going.
 
-## One line
+<InstallOsDetect />
 
-These download the matching binary for your machine, verify its checksum,
+<Tabs syncKey="install-os">
-and put it on your `PATH`.
+<TabItem label="Linux">
 
-### Linux & macOS
+**One-line installer**
 
 ```sh
 curl -fsSL https://git.lazyeval.net/oli/rdbms-playground/raw/branch/main/scripts/install.sh | sh
 ```
 
-It detects your operating system and CPU, installs to `~/.local/bin`, and
+It detects your CPU, installs to `~/.local/bin`, and prints a hint if that
-prints a hint if that directory isn't on your `PATH`. Set
+directory isn't on your `PATH`. Set `RDBMS_INSTALL_DIR` to install elsewhere,
-`RDBMS_INSTALL_DIR` to install somewhere else, or `RDBMS_VERSION=vX.Y.Z` to
+or `RDBMS_VERSION=vX.Y.Z` to pin a version. Prefer to read a script before
-pin a specific version. Prefer to read a script before running it? It lives
+running it? It lives at
-at [`scripts/install.sh`](https://git.lazyeval.net/oli/rdbms-playground/raw/branch/main/scripts/install.sh).
+[`scripts/install.sh`](https://git.lazyeval.net/oli/rdbms-playground/raw/branch/main/scripts/install.sh).
 
-### Windows (PowerShell)
+**Homebrew**
-
-```powershell
-irm https://git.lazyeval.net/oli/rdbms-playground/raw/branch/main/scripts/install.ps1 | iex
-```
-
-It downloads the matching `.exe`, verifies its checksum, installs to
-`%LOCALAPPDATA%\Programs\rdbms-playground`, and adds that folder to your
-user `PATH`. Use `-InstallDir` to choose a different location or `-Version`
-to pin a release.
-
-## Package managers
-
-### Homebrew (macOS & Linux)
 
 ```sh
 brew tap lazyeval/tap https://git.lazyeval.net/lazyeval/homebrew-tap
 brew install lazyeval/tap/rdbms-playground
 ```
 
-### Scoop (Windows)
+</TabItem>
+<TabItem label="macOS">
+
+**One-line installer**
+
+```sh
+curl -fsSL https://git.lazyeval.net/oli/rdbms-playground/raw/branch/main/scripts/install.sh | sh
+```
+
+It detects your CPU (Apple Silicon or Intel), installs to `~/.local/bin`, and
+prints a hint if that directory isn't on your `PATH`. Set `RDBMS_INSTALL_DIR`
+to install elsewhere, or `RDBMS_VERSION=vX.Y.Z` to pin a version. Prefer to
+read a script before running it? It lives at
+[`scripts/install.sh`](https://git.lazyeval.net/oli/rdbms-playground/raw/branch/main/scripts/install.sh).
+
+**Homebrew**
+
+```sh
+brew tap lazyeval/tap https://git.lazyeval.net/lazyeval/homebrew-tap
+brew install lazyeval/tap/rdbms-playground
+```
+
+</TabItem>
+<TabItem label="Windows">
+
+**One-line installer (PowerShell)**
+
+```powershell
+irm https://git.lazyeval.net/oli/rdbms-playground/raw/branch/main/scripts/install.ps1 | iex
+```
+
+It downloads the matching `.exe`, verifies its checksum, installs to
+`%LOCALAPPDATA%\Programs\rdbms-playground`, and adds that folder to your user
+`PATH`. Use `-InstallDir` to choose a different location or `-Version` to pin
+a release.
+
+**Scoop**
 
 ```sh
 scoop bucket add lazyeval https://git.lazyeval.net/lazyeval/scoop-bucket
 scoop install rdbms-playground
 ```
 
-### winget (Windows)
+**winget**
 
-:::note
 A winget package (`winget install LazyEvaluation.RdbmsPlayground`) is on its
 way and awaiting review in the public winget catalogue. Until it lands, use
 Scoop or the PowerShell one-liner above.
-:::
+
+</TabItem>
+</Tabs>
 
 ## With cargo
 
-If you have a Rust toolchain, you can install from
+These work on any platform with a Rust toolchain. Install from
 [crates.io](https://crates.io/crates/rdbms-playground):
 
 ```sh
 cargo install rdbms-playground
 ```
 
-For a faster install that fetches a prebuilt binary instead of compiling,
+For a faster install that fetches a prebuilt binary instead of compiling, use
-use [`cargo-binstall`](https://github.com/cargo-bins/cargo-binstall)
+[`cargo-binstall`](https://github.com/cargo-bins/cargo-binstall) (install it
-(install it first — it is not part of `cargo` itself):
+first — it is not part of `cargo` itself):
 
 ```sh
 cargo binstall rdbms-playground
@@ -83,11 +111,11 @@ cargo binstall rdbms-playground
 
 ## Prebuilt binaries
 
-Every release publishes static Linux, standalone Windows, and macOS
+Every release publishes static Linux, standalone Windows, and macOS binaries
-binaries (x86_64 and aarch64), each with a `.sha256` checksum, on the
+(x86_64 and aarch64), each with a `.sha256` checksum, on the
 [releases page](https://git.lazyeval.net/oli/rdbms-playground/releases).
-Download the one for your platform, make it executable if needed, and put
+Download the one for your platform, make it executable if needed, and put it
-it somewhere on your `PATH`.
+somewhere on your `PATH`.
 
 ## Run it
 

website/src/content/docs/privacy.md

@@ -0,0 +1,51 @@
+---
+title: Privacy
+description: What we measure on this site, and what we don't. No cookies, no personal data.
+tableOfContents: false
+---
+
+This site is run as a free teaching tool, not a business that profiles its
+visitors. We keep the analytics deliberately minimal.
+
+## What we collect
+
+We measure aggregate usage with **[Umami](https://umami.is/)**, a
+privacy-friendly analytics tool that we **host ourselves** (on
+`umami.oliversturm.com`). Nothing is sent to a third-party advertising
+network.
+
+For each page view we record:
+
+- the page you viewed and the site you arrived from (the referrer),
+- your browser, operating system, and device type,
+- an approximate **country**.
+
+That's it. The numbers are aggregated into counts — how many people read a
+page, which pages are popular — and are never combined into a profile of an
+individual.
+
+## What we don't do
+
+- **No cookies, and nothing stored on your device.** The tracker sets no
+  cookies and writes nothing to local storage. You can confirm this in your
+  browser's developer tools — there are no entries to clear.
+- **No personal data.** Your IP address is used for a moment on our own
+  server to derive the approximate country and to tell repeated page-loads
+  apart within a single day; it is **not stored**.
+- **No cross-site tracking.** We cannot and do not follow you to other sites,
+  and we never sell or share what we measure.
+
+## Your choices
+
+If your browser sends a **Do Not Track** signal, we honour it: those visits
+are not counted at all.
+
+Because the analytics use no cookies and store nothing on your device, there
+is no cookie banner to dismiss — there is simply nothing to consent to.
+
+## Questions
+
+This site and its analytics are operated by
+[Lazy Evaluation Ltd](https://www.lazyevaluation.biz/). If you have any
+questions about what we measure, get in touch through the contact details
+there.