Surface GPL-3 / open-source status across the site

Add a one-liner under the Install page H1, a sentence in the packages
overview intro, and a site-wide footer note linking to GPL-3.0 and the
GitHub source.

Author: christophsax

.vitepress/config.js

@@ -77,7 +77,7 @@ module.exports = {
     ],
     footer: {
       message: `Developed by <a href="https://cynkra.com" target="_blank"><img src="${base}logos/logo-cynkra.png" alt="cynkra" style="height:36px;vertical-align:middle"></a> and <a href="https://www.bms.com" target="_blank"><img src="${base}logos/logo-bms.png" alt="BMS" style="height:24px;vertical-align:middle"></a>`,
-      copyright: ''
+      copyright: `Free and open source, released under <a href="https://www.gnu.org/licenses/gpl-3.0.html" target="_blank">GPL-3.0</a>. <a href="https://github.com/BristolMyersSquibb/blockr" target="_blank">Source on GitHub</a>.`
     },
   }
 }

install.md

@@ -5,6 +5,8 @@ description: Install the blockr meta-package and optional extras.
 
 # Install blockr
 
+blockr is free and open source, released under [GPL-3.0](https://www.gnu.org/licenses/gpl-3.0.html).
+
 You need [R](https://www.r-project.org/) 4.1 or later. Most users access blockr through a hosted server (e.g. [blockr.cloud](https://blockr.cloud)) and don't need to install anything locally.
 
 ## blockr <Badge type="tip" text="recommended" />

packages/index.md

@@ -12,6 +12,10 @@ app (engine, layout, sessions, code export) and **block packages** that
 provide the actual building blocks users drag onto a board. Each layer spans
 three maturity tiers — stable on CRAN, in development, and experimental.
 
+All packages are free and open source, released under
+[GPL-3.0](https://www.gnu.org/licenses/gpl-3.0.html).
+Source for each package lives on GitHub (linked from the cards below).
+
 ::: tip Just want to get started?
 `install.packages("blockr")` pulls the whole stable stack in one step — the
 **blockr** meta‑package re‑exports the six CRAN packages below.