refactor(ev): pass ev object directly to EV entity ctors

[mrebbert]

Summary

Fourth (and last) candidate from the post-0.1.53 refactor audit.

Every EV setup site unpacked `ev.id()`, `ev.manufacturer()`, `ev.model()` into three positional args, then passed them to the constructor which reassembled them into a `DeviceInfo`. Two subclasses (`Select` / `Time`) additionally accepted the whole `ev_charger` and stored it on `self._ev_charger` — a field that was never read (all reads route through the parent's `_get_ev()`).

• `OneKomma5EVEntity` now takes the `ev` object directly and reads `.id()` / `.manufacturer()` / `.model()` internally.
• `Sensor` / `Number` / `Select` / `Time` subclasses drop three positional args each.
• The two dead `self._ev_charger` fields are gone.

Net −86 lines across 6 files (mostly disappearing setup boilerplate).

Stability contract

Unique-id and `stable_object_id` formulas are unchanged (`f"{system_id}{ev.id()}{suffix}"`) — statistics, automations, and existing `entity_id`s all survive.

Test plan

• Full suite green (`.venv/bin/pytest -q` → 226 passed).
• mypy + ruff clean.
• Live-deployed on homie; all four EV entity platforms still register with correct state:
  • `select.volkswagen_id_4_lademodus` → `quick_charge`
  • `time.volkswagen_id_4_abfahrtzeit` → `06:30:00`
  • `number.volkswagen_id_4_ziel_akkustand` → `80.0`
  • `sensor.volkswagen_id_4_ziel_akkustand` → `80.0`, `sensor.garage_elektrofahrzeug_batteriekapazitat` → `77.0`, and more.

Independence

Touches EV entity plumbing only. No overlap with #12 (`init.py` + price-sensor MRO) or #13 (`coordinator.py`).