Fix resume not resetting temp soll for steps that inherit temperature

Steps with no 'temperature' field inherit their target from a prior step
(temperature=None in the resolved schedule). The resume-from-pause code
only called set_theta_soll when the current step had an explicit temperature,
so any manual setpoint change made during pause was never reverted for
inherited steps (e.g. sud_0010 steps 2-3 both hold at step 1's 57 °C).

Fix: save theta_soll_set at pause time; use it as fallback on resume when
the current step's temperature is None. Also set initialTempSollSync=true
in the browser on play so the slider accepts the next server Soll push
regardless of message arrival order relative to the State update.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01SH2D4LRuCnhLSzoYerAfJX

web/app.js

@@ -672,6 +672,12 @@ function onSudChanged(msg) {
 				closedLoop = true;
 				document.getElementById('closed-loop').checked = true;
 				sendMsg('Heater', {ClosedLoop: true});
+				// Accept the next Soll push from the server even if it
+				// arrives before sudRunning has gone true at this client
+				// (the two messages are sent as separate tasks server-side,
+				// so arrival order is non-deterministic in edge cases).
+				initialTempSollSync = true;
+				initialHeatrateSync = true;
 				elapsed = 0;
 				energyByStep = {};
 				energyCurrent = 0;