feat(optimization): deadlines for consumers and EV, graded grid export

Three related scheduling improvements, all opt-in and behaviour-preserving
when the new fields are not set.

Flexible consumers get absolute time bounds next to the recurring
time_windows: earliest_start_datetime and deadline_datetime, where the
deadline requires the complete run to have *finished* before that moment
("clean dishes by 03:00 tonight"). When no start can meet it,
deadline_policy decides between BEST_EFFORT (run as early as possible, so
the delay rather than the cost is minimized) and STRICT (keep the
deadline; a ONCE consumer then fails the optimization). The solution
reports appliance_deadline_missed per device.

The EV charging target can be given the same kind of deadline, as an
absolute min_soc_deadline_datetime and/or a relative min_soc_max_duration_h
("full in 6 hours"), the earlier of the two winning. The ev_soc_miss
penalty is then evaluated at that slot instead of at the end of the
horizon, and the seeding heuristic only proposes charge slots before it.

Battery-to-grid export under direct marketing is no longer all-or-nothing:
grid_export_rates configures the selectable export levels as a factor of
the rated discharge power (default [0.25, 0.5, 0.75, 1.0]). Each rate is
its own optimizer state, with the full-power state keeping its previous
index so existing seeds and heuristics are unaffected. The chosen level
per slot is reported in battery_grid_export_factor and as the
GRID_SUPPORT_EXPORT operation factor.

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

docs/_generated/configdevices.md

@@ -49,6 +49,12 @@
                        0.9,
                        1.0
                    ],
+                   "grid_export_rates": [
+                       0.25,
+                       0.5,
+                       0.75,
+                       1.0
+                   ],
                    "min_soc_percentage": 0,
                    "max_soc_percentage": 100
                }
@@ -76,6 +82,12 @@
                        0.9,
                        1.0
                    ],
+                   "grid_export_rates": [
+                       0.25,
+                       0.5,
+                       0.75,
+                       1.0
+                   ],
                    "min_soc_percentage": 0,
                    "max_soc_percentage": 100
                }
@@ -120,6 +132,12 @@
                        0.9,
                        1.0
                    ],
+                   "grid_export_rates": [
+                       0.25,
+                       0.5,
+                       0.75,
+                       1.0
+                   ],
                    "min_soc_percentage": 0,
                    "max_soc_percentage": 100,
                    "measurement_key_soc_factor": "battery1-soc-factor",
@@ -159,6 +177,12 @@
                        0.9,
                        1.0
                    ],
+                   "grid_export_rates": [
+                       0.25,
+                       0.5,
+                       0.75,
+                       1.0
+                   ],
                    "min_soc_percentage": 0,
                    "max_soc_percentage": 100,
                    "measurement_key_soc_factor": "battery1-soc-factor",
@@ -470,6 +494,7 @@ of the two must be provided.
 | charging_efficiency | `float` | `rw` | `0.88` | Charging efficiency [0.01 ... 1.00]. |
 | device_id | `str` | `rw` | `<unknown>` | ID of device |
 | discharging_efficiency | `float` | `rw` | `0.88` | Discharge efficiency [0.01 ... 1.00]. |
+| grid_export_rates | `Optional[list[float]]` | `rw` | `[0.25, 0.5, 0.75, 1.0]` | Battery-to-grid export rates as factor of maximum discharge power ]0.00 ... 1.00]. Only used with direct marketing (feedintariff.direct_marketing_enabled). Each rate is one additional optimizer state; [1.0] restores all-or-nothing export. None triggers fallback to default export-rates. |
 | levelized_cost_of_storage_kwh | `float` | `rw` | `0.0` | Levelized cost of storage (LCOS), applied once to each kWh delivered by the battery [€/kWh]. |
 | max_charge_power_w | `Optional[float]` | `rw` | `5000` | Maximum charging power [W]. |
 | max_soc_percentage | `int` | `rw` | `100` | Maximum state of charge (SOC) as percentage of capacity [%]. |
@@ -508,6 +533,12 @@ of the two must be provided.
                        0.75,
                        1.0
                    ],
+                   "grid_export_rates": [
+                       0.25,
+                       0.5,
+                       0.75,
+                       1.0
+                   ],
                    "min_soc_percentage": 10,
                    "max_soc_percentage": 100
                }
@@ -541,6 +572,12 @@ of the two must be provided.
                        0.75,
                        1.0
                    ],
+                   "grid_export_rates": [
+                       0.25,
+                       0.5,
+                       0.75,
+                       1.0
+                   ],
                    "min_soc_percentage": 10,
                    "max_soc_percentage": 100,
                    "measurement_key_soc_factor": "battery1-soc-factor",