fix: make sim_warp_factor real-hardware-safe and sud logs forecast-reproducible

sim_warp_factor was scaling DT_TASK unconditionally, including against real
hardware, and was leaking into recorded sample timestamps via wall-clock
time - both violate its intended meaning (a reciprocal scale on task wait
time only). Clamp it to 1.0 whenever Heater.type isn't "sim", and track
elapsed time via tick-counted accumulators (Sud.elapsed for SudLogTask, a
matching one for ServerLogTask) instead of time.monotonic().

Sud/server logs now also carry HeaterPowers, the effective SimWarpFactor,
the raw Doc, a correct Name, and ForecastAnchors (one entry per real
_reanchor_forecast() trigger) - enough for utils/analyze_log.py to rebuild
a SudForecastEstimator and replay the exact same splice-per-transition
forecast correction offline that a live client sees, replacing the old
(always-dead) forecast_*.json sidecar lookup.

Two bugs found and fixed along the way:
- ServerLogTask's periodic wall-clock checkpoint had no way to know a
  SudLogTask run had just ended, so it would immediately re-write the
  just-completed log with PlantParams/ForecastAnchors cleared back to
  empty. Gated the checkpoint on _should_sample().
- _reanchor_forecast() truncated the old forecast against real elapsed
  time, which can end up numerically less than the old forecast's own
  (very wrong) speculative timestamps once a WAIT_USER confirmation runs
  long - leaving a "ghost" segment instead of a clean cut. Truncate
  against forecast_step_starts[index] instead, which lives in the same
  coordinate space as the forecast being cut.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01JFDeoTKBDkXRhPfnyDEoBt

tasks/server_log.py

@@ -16,7 +16,7 @@ class ServerLogTask(ATask):
 	Sud state — useful for verifying controller and heater behaviour
 	outside of a scheduled brew."""
 
-	def __init__(self, tc: APid, heater: AHeater, heater_task, interval, path='./logs', config=None, dt=None, log_interval=None):
+	def __init__(self, tc: APid, heater: AHeater, heater_task, interval, path='./logs', config=None, dt=None, log_interval=None, sim_warp_factor=None):
 		ATask.__init__(self, interval)
 		self.tc = tc
 		self.heater = heater
@@ -25,14 +25,15 @@ class ServerLogTask(ATask):
 		self.config = config
 		self.dt = dt
 		self.log_interval = log_interval
+		self.sim_warp_factor = sim_warp_factor
 		self._samples = []
 		self._param_events = []
-		self._t0 = time.monotonic()
+		self._elapsed_total = 0.0
 		self._run_id = time.strftime("%Y%m%dT%H%M%S", time.localtime())
-		self._last_write = self._t0
+		self._last_write = time.monotonic()
 
 	def log_plant_params(self, elapsed, params):
-		self._param_events.append({'t': time.monotonic() - self._t0, 'params': params})
+		self._param_events.append({'t': elapsed, 'params': params})
 
 	async def on_process(self):
 		while True:
@@ -40,20 +41,42 @@ class ServerLogTask(ATask):
 				self._samples.append(self._take_sample())
 			# Periodically checkpoints to disk (same file, overwritten whole
 			# each time - see write()) so a hard crash/power loss only loses
-			# up to log_interval seconds, not the whole session/run.
+			# up to log_interval seconds, not the whole session/run. This
+			# checkpoint cadence is deliberately real (wall-clock) time,
+			# unlike _elapsed() below - it's bounding real data-loss risk,
+			# not tracking brew progress.
 			now = time.monotonic()
-			if self.log_interval and now - self._last_write >= self.log_interval:
+			# Gated on _should_sample(): for SudLogTask, a completed run's
+			# stop_run() already wrote the correct final state and cleared
+			# _param_events for the *next* run - an unguarded checkpoint
+			# here would otherwise fire on the very next iteration (once
+			# log_interval real seconds have passed since the last one,
+			# regardless of the run having ended in between) and clobber
+			# that already-correct file with _samples unchanged but
+			# _param_events now empty.
+			if self.log_interval and self._should_sample() and now - self._last_write >= self.log_interval:
 				self.write()
 				self._last_write = now
 			await asyncio.sleep(self.interval)
+			self._elapsed_total += self.dt
 
 	def _should_sample(self):
 		return True
 
+	def _elapsed(self):
+		"""Simulated seconds elapsed since this task started sampling -
+		tick-counted (advances by self.dt once per on_process() iteration),
+		never derived from wall-clock time: under sim_warp_factor, real and
+		simulated time diverge (see components/sud.py's Sud.elapsed, and
+		the README's "Forecast vs. actual duration" section, for the same
+		reasoning), so a wall-clock 't' would desync from the forecast's
+		own tick-counted timeline it's meant to be compared against."""
+		return self._elapsed_total
+
 	def _take_sample(self):
 		power_set = max(self.heater_task.power_soll, self.heater_task.power_actor)
 		return {
-			't':         time.monotonic() - self._t0,
+			't':         self._elapsed(),
 			'timestamp': time.time(),
 			'temp_ist':  self.tc.theta_ist,
 			'temp_soll': self.tc.theta_soll_set,
@@ -66,19 +89,38 @@ class ServerLogTask(ATask):
 	def _filename(self):
 		return 'log_{}.json'.format(self._run_id)
 
+	def _extra_log_data(self):
+		"""Hook for subclasses (SudLogTask) to contribute additional keys
+		to write()'s output - see there."""
+		return {}
+
+	def _log_name(self):
+		"""Hook for subclasses (SudLogTask) - a server-session log covers
+		the whole process lifetime rather than one named run, so it has
+		none of its own."""
+		return ''
+
 	def write(self):
 		if not self._samples:
 			return
 		os.makedirs(self.path, exist_ok=True)
 		filename = self._filename()
 		path = os.path.join(self.path, filename)
-		log_data = {'Name': ''}
+		log_data = {'Name': self._log_name()}
 		if self.dt is not None:
 			log_data['dt'] = self.dt
+		if self.sim_warp_factor is not None:
+			log_data['SimWarpFactor'] = self.sim_warp_factor
 		if self.config is not None:
 			log_data['Config'] = self.config
+		# Queried live from the connected device rather than reconstructed
+		# offline (utils/analyze_log.py has no hardware to ask) - needed to
+		# reproduce this run's SudForecastEstimator (see components/
+		# sud_forecast.py) for a post-hoc forecast-vs-actual comparison.
+		log_data['HeaterPowers'] = self.heater.get_powers()
 		if self._param_events:
 			log_data['PlantParams'] = self._param_events
+		log_data.update(self._extra_log_data())
 		log_data['Samples'] = self._samples
 		with open(path, 'w') as f:
 			json.dump(log_data, f, indent='\t')