feat: build out the /plugins page

The nav and footer have linked to /plugins since the start, but no
route or page existed, so it rendered blank. Adds the page per the
docs/PAGES.md spec — plugin building blocks, the four built-in
plugins, a step-by-step "writing a plugin" guide with real code from
netork/plugins/, and the fire/call/transform hook bus — sourced from
the actual plugin system in the main NetOrk repo for accuracy.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/App.tsx

@@ -7,6 +7,7 @@ import Drivers from './pages/Drivers'
 import GettingStarted from './pages/GettingStarted'
 import Roadmap from './pages/Roadmap'
 import Nis2 from './pages/Nis2'
+import Plugins from './pages/Plugins'
 
 export default function App() {
   return (
@@ -21,6 +22,7 @@ export default function App() {
             <Route path="/docs/getting-started" element={<GettingStarted />} />
             <Route path="/roadmap" element={<Roadmap />} />
             <Route path="/nis2" element={<Nis2 />} />
+            <Route path="/plugins" element={<Plugins />} />
           </Routes>
         </main>
         <Footer />