v0.2.0-beta2

New: device pickers for setup, instead of hunting down individual entities.

• Vehicle step now asks 'which Tesla device?' (device_resolve.py auto-resolves battery/odometer/tracker/charging/lock/outside-temp entities from it)
• Zaptec/Monta steps likewise ask 'which charger device?' — Monta's wallet balance is resolved from its sibling account device automatically
• The old manual entity-picker forms are still there as a fallback, shown only when something couldn't be auto-detected, or via editable defaults if it is
• Built for multi-vehicle/multi-charger households — each EV Ledger entry picks its own specific device