Add explicit initial grain_mass/water_mass to the Sud doc

Sud now parses top-level grain_mass/water_mass (sibling to pot_mass/
pot_material/L/Td, defaulting to 0/0) - what's actually in the pot before
the brew starts, as opposed to default.step's grain_mass/water_mass, which
is just inert template filler. All sude/*.json docs gain explicit values
matching what their first step already resolved to.

tasks/sud.py's apply_plant_params() now takes grain_mass/water_mass
directly instead of a step dict: on_step_changed() still passes the active
step's own (these vary as malt goes in/water boils off), but the Load
handler now reads Sud.grain_mass/water_mass directly instead of parsing
schedule[0]. The GUI's status-line mass preview (shown immediately on
Load, before Start) does the same.

Also fixes a latent bug found along the way: _continue_forecast_after_confirm()'s
reconstructed sub-doc was missing L/Td/grain_mass/water_mass entirely,
silently falling back to generic defaults instead of the real Sud's own
values - invisible only because every current sude/*.json happens to use
those same defaults.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01DkkuG48uHFCGKe6dPSERFk

components/sud.py

@@ -66,6 +66,14 @@ EMPTY_SUD = {
 	# values brewpi.py used to hardcode for every brew alike.
 	'L': 0.2,
 	'Td': 30,
+	# Initial grain_mass/water_mass - what's actually in the pot before
+	# the brew starts (e.g. water added but no malt yet), as opposed to
+	# default.step's grain_mass/water_mass, which is just inert template
+	# filler for steps that don't override it. Lets a caller derive
+	# starting plant params directly (see SudTask.recv()'s Load handler)
+	# without having to parse the first step out of the schedule.
+	'grain_mass': 0,
+	'water_mass': 0,
 	'steps': [],
 }
 
@@ -80,7 +88,8 @@ class Sud(AttributeChange):
 		self._data = EMPTY_SUD
 
 		(self.name, self.description, self.schedule, self.pot_mass,
-			self.pot_material, self.L, self.Td) = self._parse_data(self._data)
+			self.pot_material, self.L, self.Td, self.grain_mass,
+			self.water_mass) = self._parse_data(self._data)
 
 		self._paused_from = None
 		self._reset_run_state()
@@ -88,9 +97,10 @@ class Sud(AttributeChange):
 	@staticmethod
 	def _parse_data(data):
 		"""Parses a sud.json document into the (name, description, schedule,
-		pot_mass, pot_material, L, Td) tuple Sud needs. Computed up front
-		rather than assigned straight onto self, so a malformed load()
-		can't leave a half-applied schedule in place."""
+		pot_mass, pot_material, L, Td, grain_mass, water_mass) tuple Sud
+		needs. Computed up front rather than assigned straight onto self,
+		so a malformed load() can't leave a half-applied schedule in
+		place."""
 		name = data.get('Name', '')
 		description = data.get('Description', '')
 
@@ -101,8 +111,10 @@ class Sud(AttributeChange):
 		pot_material = data.get('pot_material')
 		L = data.get('L', EMPTY_SUD['L'])
 		Td = data.get('Td', EMPTY_SUD['Td'])
+		grain_mass = data.get('grain_mass', EMPTY_SUD['grain_mass'])
+		water_mass = data.get('water_mass', EMPTY_SUD['water_mass'])
 
-		return name, description, schedule, pot_mass, pot_material, L, Td
+		return name, description, schedule, pot_mass, pot_material, L, Td, grain_mass, water_mass
 
 	def _reset_run_state(self):
 		"""Resets run-time progress back to a freshly-loaded, not-yet-started
@@ -136,7 +148,8 @@ class Sud(AttributeChange):
 			return False
 
 		(self.name, self.description, self.schedule, self.pot_mass,
-			self.pot_material, self.L, self.Td) = parsed
+			self.pot_material, self.L, self.Td, self.grain_mass,
+			self.water_mass) = parsed
 		self._data = data
 
 		self._reset_run_state()