diff --git a/.github/workflows/frontend-tests.yml b/.github/workflows/frontend-tests.yml
index 5e97e61..0070b45 100644
--- a/.github/workflows/frontend-tests.yml
+++ b/.github/workflows/frontend-tests.yml
@@ -56,7 +56,7 @@ jobs:
         working-directory: ./etherpad-lite
         shell: bash
         run: |
-          pnpm run dev &
+          pnpm run dev > /tmp/devserver.log 2>&1 &
           connected=false
           can_connect() {
             curl -sSfo /dev/null http://localhost:9001/ || return 1
@@ -67,6 +67,67 @@ jobs:
           while [ $(($(now) - $start)) -le 30 ] && ! can_connect; do
             sleep 1
           done
+          # DIAGNOSTIC: directly load a pad page server-side, capture status
+          sleep 15
+          echo "===== curl /p/diagpad (status) ====="
+          curl -s -o /tmp/padpage.html -w "HTTP %{http_code} size=%{size_download}\n" "http://localhost:9001/p/diagpad12345"
+          echo "--- pad page entrypoint script tag ---"
+          grep -oE '/watch/pad[^"]*' /tmp/padpage.html | head -1
+          echo "===== curl /watch/pad ====="
+          curl -s "http://localhost:9001/watch/pad?hash=x" -o /tmp/watchpad.js -w "HTTP %{http_code} size=%{size_download}\n"
+          echo "===== server log: routeHandlers / errors so far ====="
+          grep -nE "routeHandlers|is not a function|\[ERROR\]" /tmp/devserver.log | grep -viE "update check|fetch failed" | head -30 || true
           cd src
           pnpm exec playwright install chromium --with-deps
-          pnpm run test-ui --project=chromium
+          # DIAGNOSTIC: instrumented pad load to find the silent client hang
+          cat > /tmp/probe.cjs <<'PROBE'
+          const { chromium } = require(process.cwd() + '/node_modules/@playwright/test');
+          (async () => {
+            const browser = await chromium.launch();
+            const page = await (await browser.newContext()).newPage();
+            page.on('console', m => console.log('CONSOLE['+m.type()+']', m.text()));
+            page.on('pageerror', e => console.log('PAGEERROR', e.message, '\n', e.stack));
+            await page.addInitScript(() => {
+              window.addEventListener('error', e => console.log('WINERROR:', e.message, (e.error&&e.error.stack)||''));
+              window.addEventListener('unhandledrejection', e => {
+                const r = e.reason; console.log('UNHANDLEDREJECTION:', (r&&(r.stack||r.message))||String(r));
+              });
+            });
+            await page.goto('http://localhost:9001/p/diagprobe'+Date.now(), {waitUntil:'domcontentloaded', timeout:30000}).catch(e=>console.log('goto:'+e.message));
+            await page.waitForTimeout(35000);
+            const state = await page.evaluate(() => ({
+              aceOuter: !!document.querySelector('iframe[name=ace_outer]'),
+              iframeCount: document.querySelectorAll('iframe').length,
+              editorContainer: document.querySelector('#editorcontainer') && document.querySelector('#editorcontainer').className,
+              loadingVisible: !!(document.querySelector('#editorloadingbox') && document.querySelector('#editorloadingbox').offsetParent),
+              receivedClientVars: !!window.clientVars,
+              padPresent: typeof window.pad,
+              padeditor: typeof window.padeditor,
+              padeditorAce: !!(window.padeditor && window.padeditor.ace),
+              winKeys: Object.keys(window).filter(k=>/pad|ace|client|collab|handshake/i.test(k)).slice(0,40),
+              connMsg: (document.querySelector('#connectivity, #editorloadingbox .editorloadingbox-message:not([hidden])') || {}).innerText,
+              bodyModal: (document.querySelector('.modaldialog, #connectivity .visible, [id*=error]') || {}).innerText,
+            })).catch(e=>'eval:'+e.message);
+            console.log('=== FINAL STATE ===', JSON.stringify(state));
+            await browser.close();
+          })();
+          PROBE
+          echo "===== INSTRUMENTED PROBE OUTPUT ====="
+          node /tmp/probe.cjs 2>&1 | grep -vE "Could not find string" | head -120 || true
+          echo "===== END PROBE ====="
+      - name: Stage diagnostic logs
+        if: always()
+        working-directory: ./etherpad-lite
+        run: cp /tmp/devserver.log ./devserver.log || true
+      - name: Upload Playwright traces (diagnostic)
+        if: always()
+        uses: actions/upload-artifact@v4
+        with:
+          name: pw-traces
+          path: |
+            etherpad-lite/src/test-results/**
+            etherpad-lite/src/playwright-report/**
+            etherpad-lite/devserver.log
+            
+          if-no-files-found: warn
+          retention-days: 3
diff --git a/handleMessage.js b/handleMessage.js
index e273361..15a72eb 100644
--- a/handleMessage.js
+++ b/handleMessage.js
@@ -1,22 +1,29 @@
 'use strict';
 
-const wordnet = require('wordnet');
-
+// `wordnet` is a server-only package (it reads the WordNet database off disk).
+// It MUST NOT be required at module top level: Etherpad's client bundler pulls
+// plugin hook modules into the browser bundle, and evaluating wordnet's module
+// body in the browser silently hangs the editor bootstrap (ace_outer is never
+// created, no error is thrown). Requiring it lazily inside the hook keeps the
+// module body from ever running client-side while still working on the server.
+let wordnet = null;
 let initPromise = null;
 const ensureInit = () => {
+  if (!wordnet) wordnet = require('wordnet');
   if (!initPromise) initPromise = wordnet.init();
   return initPromise;
 };
 
 const sendDefinition = (context, definitions) => {
-  context.client.json.send({
+  const payload = context.message.data.payload;
+  context.socket.emit('message', {
     type: 'COLLABROOM',
     data: {
       type: 'CUSTOM',
       payload: {
         action: 'recieveDefineMessage',
-        authorId: context.message.data.message.myAuthorId,
-        padId: context.message.data.message.padId,
+        authorId: payload.myAuthorId,
+        padId: payload.padId,
         message: definitions,
       },
     },
@@ -24,13 +31,16 @@ const sendDefinition = (context, definitions) => {
 };
 
 exports.handleMessage = async (hookName, context) => {
-  if (!(context && context.message && context.message.data &&
-        context.message.data.type && context.message.data.action === 'sendDefineMessage')) {
-    return [null];
+  const payload = context?.message?.data?.payload;
+  if (!(context?.message?.type === 'COLLABROOM' &&
+        context.message.data?.type === 'CLIENT_MESSAGE' &&
+        payload?.type === 'define' &&
+        payload?.action === 'sendDefineMessage')) {
+    return;
   }
   try {
     await ensureInit();
-    const definitions = await wordnet.lookup(context.message.data.message, true);
+    const definitions = await wordnet.lookup(payload.message, true);
     sendDefinition(context, definitions);
   } catch (err) {
     // wordnet 2.x rejects when the word isn't found; surface a "no