Add Pause to the browser client's Sud controls

Mirrors client/brewpi_gui.py's actionPause: btn-sud-pause sends
{"Sud": {"Pause": true}} and is only enabled while actually running
(not idle, not already paused), matching update_sud_actions()'s
enabled/disabled logic - Start already doubles as Resume while paused,
so no separate Resume control is needed.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0189FkmyJkY77HqsNomr1DwV

web/index.html

@@ -17,6 +17,7 @@
 		<input type="file" id="sud-file-input" accept="application/json" class="hidden">
 		<button id="btn-sud-save">Save&hellip;</button>
 		<button id="btn-sud-start">Start</button>
+		<button id="btn-sud-pause">Pause</button>
 		<button id="btn-sud-stop">Stop</button>
 	</span>
 </header>