feat: add site-wide glossary with hover tooltips

Every abbreviation and technical term used in the site's copy (RBAC,
NAPALM, config drift, ...) now links to a new /glossary page and shows
a short definition on hover, wherever it appears in body text. Product
and vendor brand names are deliberately excluded — the glossary stays
a dictionary of vocabulary, not a company directory.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

src/App.tsx

@@ -8,6 +8,7 @@ import GettingStarted from './pages/GettingStarted'
 import Roadmap from './pages/Roadmap'
 import Nis2 from './pages/Nis2'
 import Plugins from './pages/Plugins'
+import Glossary from './pages/Glossary'
 
 export default function App() {
   return (
@@ -23,6 +24,7 @@ export default function App() {
             <Route path="/roadmap" element={<Roadmap />} />
             <Route path="/nis2" element={<Nis2 />} />
             <Route path="/plugins" element={<Plugins />} />
+            <Route path="/glossary" element={<Glossary />} />
           </Routes>
         </main>
         <Footer />