Configure Edge and Brave too, not just Chrome

They are Chromium: same CRX, same update manifest, same policy — only the
registry vendor key differs. The script now defaults to every one of the three
it finds installed, which is what the Linux counterpart already did.

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

setup-windows.bat

@@ -331,9 +331,10 @@ REM the extension is installed the way a self-hosted one has to be: a policy
 REM entry naming our update server. Written to this user's hive, which needs no
 REM elevation - install-extension-policy.ps1 -Scope Machine covers every account.
 echo.
-echo  [7/7] Chrome extension
-echo        Installs it from the update server and lets Chrome keep it current
-echo        by itself. No administrator rights needed.
+echo  [7/7] Browser extension
+echo        Installs it from the update server into whichever of Chrome, Edge
+echo        and Brave are present, and lets them keep it current by themselves.
+echo        No administrator rights needed.
 set "DOEXT="
 set /p "DOEXT=      Set this up now? [Y/n] "
 if /i "%DOEXT%"=="n" goto :ext_skipped