feat(ezo_types): ORP extended-scale readback + refresh button; drop datalogger #5

The RTD datalogger and ORP extended-scale switches were write-only, so on
boot they showed their default rather than the circuit's actual state.
Mirror the cell-constant/TDS readback: the switches query D,? / ORPext,?
in setup(), and parse_*_response_ publishes the parsed state to the switch
(display-only, no write-back) via a back-pointer from the sensor.
Add a "Refresh Circuit State" template button that re-queries every
readback entity (cell constant, TDS factor, datalogger, extended scale)
on demand -- useful for re-syncing after runtime changes without a reboot.
Hardware-verified with the button: the circuits return their real state
(?D,60, ?ORPEXT,1, ?K,1.00, ?TDS,0.50) and each entity updates. Note the
datalogger and extended scale are NOT power-retained (per the RTD
datasheet retained list), so they reset to off on every power cut/reboot;
the startup readback reflects that correctly, and the button re-syncs
after runtime changes.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Document the component now that it's feature-complete: the four circuit
types and their config keys, the temperature-compensation model, and the
state-readback behavior.
The temperature section spells out the C-only stance -- pH/EC/ORP
compensation is Celsius by protocol, so the RTD reports C and the
component deliberately does not expose a circuit-scale control (a footgun
that would silently corrupt compensation). Displaying F/K is a
presentation concern; document the copy-sensor pattern for it instead.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

The RTD datalogger can be enabled over I2C (D,n), but its stored readings
can only be bulk-recalled with M,all in UART mode -- the I2C command set
only offers single-slot M (which walks an internal pointer) and M,?. So
over I2C there is no clean way to surface the 50 logged points; a logger
toggle would be a write-only control whose captured data you cannot read
back.
Rather than ship that half-feature, remove datalogger support entirely:
the DataloggerSwitch, the RTD D,? readback, the `datalogger:` config key,
and its docs. The ORP extended-scale readback added alongside it stays.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Enabling extended scale widens the ORP range from ±1020 mV to ±2040 mV
but halves accuracy from ±1 mV to ±2 mV. Note it in the orp config-var
docs and the example comment so it reads as a range-vs-accuracy trade,
not free headroom.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>