fix: preserve EVSE and connector IDs in configuration persistence

fix: preserve EVSE and connector IDs in configuration persistence

Serialization (buildConnectorsStatus, buildEvsesStatus) now saves
[id, status] tuples instead of flat arrays, preserving EVSE and
connector IDs per OCPP 2.0.1 §7.

Deserialization detects both formats transparently: new tuple format
uses explicit IDs, legacy flat array format falls back to array index.

Add checkEvsesConfiguration template validation enforcing §7.2
connector numbering (EVSE 0: connector 0 only, EVSE ≥1: connectors
start at 1).

Add tests for ID preservation across serialization for both connectors
and EVSEs.