feat: rename remaining German API fields and deprecate legacy endpoints (#1164)

Complete the English API translation started in #675:

- rename input fields pv_akku to pv_battery and eauto to ev, and the
  solution fields eautocharge_hours_float to ev_charge_hours_float and
  eauto_obj to ev_obj; the German names are still accepted on input
  via validation aliases and re-emitted in responses as deprecated
  computed fields, same pattern as #675
- mark the legacy endpoints /strompreis, /gesamtlast and
  /gesamtlast_simple as deprecated in the OpenAPI schema
- use amount instead of a euro reference in the battery LCOS log
  message

Co-authored-by: Tobias Welz <tobias.wizneteu@gmail.com>

src/akkudoktoreos/devices/genetic/inverter.py

@@ -60,7 +60,7 @@ class Inverter:
                 remaining_load_evq = (generation - consumption) * (1.0 - scr)
 
                 if remaining_load_evq > 0:
-                    # Akku muss den Restverbrauch decken
+                    # The battery must cover the remaining consumption
                     if self.battery:
                         # Request more DC from battery to account for DC→AC conversion loss
                         dc_request = remaining_load_evq / dc_to_ac_eff
@@ -75,7 +75,7 @@ class Inverter:
                     else:
                         from_battery_ac = 0.0
 
-                    # Wenn der Akku den Restverbrauch nicht vollständig decken kann, wird der Rest ins Netz gezogen
+                    # If the battery cannot fully cover the remaining consumption, the rest is drawn from the grid
                     if remaining_load_evq > 0:
                         grid_import += remaining_load_evq
                         remaining_load_evq = 0