fix: device protocol correctness

[eman]

Fifth batch from the comprehensive repo evaluation: fixes for what the library actually sends to (and decodes from) the physical appliance.

Bugs fixed

• Malformed schedule commands (mqtt/control.py, _base.py): update_weekly_reservation() and configure_recirculation_schedule() dumped their schedule models as-is, which:

  1. double-nested the payload (request.reservation.reservation / request.schedule.schedule) — inconsistent with the documented flat shape update_reservations() sends, and
  2. leaked pydantic computed_fields into the command — enabled, days, time, mode_name, and a unit-converted temperature (e.g. 140.0 °F) alongside the raw half-Celsius param: 120.

  Both now send flat lists of raw protocol entries via a new NavienBaseModel.to_protocol_dict() helper (declared fields only, by alias).

• Command queue reordering (mqtt/command_queue.py): a command that failed mid-flush was re-queued at the tail, behind newer commands — [power_on, set_temp] became [set_temp, power_on] on the next flush. The queue is now a deque and failed commands are re-inserted at the front.

• Stale command replay (mqtt/command_queue.py, mqtt/utils.py): QueuedCommand.timestamp was stored but never checked, so a multi-hour outage replayed hours-old set_power/set_dhw_temperature commands to a physical water heater on reconnect. Commands older than MqttConnectionConfig.max_queued_command_age (default 300 s; None disables) are now discarded at send time with a warning.

• Sub-zero Fahrenheit off-by-one (temperature.py): the ASYMMETRIC rounding formula used Python's floored % (always non-negative: -11 % 10 == 9) where the firmware/NaviLink app uses a truncated remainder (-1). Raw -11 (-5.5 °C) decoded to 22 °F vs the app's 23 °F — routine for the outdoor temperature sensor in winter. Now uses math.fmod semantics; positive values unchanged.

• Freeze protection defaults in the wrong unit domain (models/status.py): defaults 43/65 were Fahrenheit display values stored in raw half-Celsius fields, decoding to 70.7 °F / 90.5 °F when the device omits the fields — any UI clamping a slider to them would allow out-of-range setpoints. Corrected to raw 12/20 = 43 °F / 50 °F, matching the fixed limits documented in data_conversions.rst.

• Missing error-change events (mqtt/state_tracker.py): error_detected fired only on 0 → non-zero; an E799 → E407 transition emitted nothing, so consumers kept displaying the stale error.

• TOU price encoding (encoding.py): encode_price() used round() (banker's rounding), under-encoding exact halves at even boundaries (0.125 @ dp=2 → 12 instead of 13); now Decimal ROUND_HALF_UP. build_tou_period() treated bool prices as pre-encoded integers (True → price 1) because bool subclasses int.

• Protocol doc errors (encoding.py, temperature.py): enable-flag convention documented inverted (1=enabled instead of 2=enabled); build_reservation_entry() example showed week: 158 for Mon/Wed/Fri instead of 84 (64+16+4); temperature doctests showed int raw values where floats are returned (all temperature.py doctests now actually pass).

Tests

New tests/test_protocol_correctness.py (17 tests): exact payload shape for both schedule commands, to_protocol_dict() exclusions, queue order preservation across failed flushes, expiry (incl. None disable and overflow), negative/positive ASYMMETRIC conversions, freeze defaults, error-change/unchanged/cleared events, half-up price encoding, bool/int TOU price handling.

Validation

• pytest: 525 passed
• ruff check / ruff format --check: clean
• pyright src/nwp500: 0 errors
• mypy src/nwp500: no issues

[Copilot]

Pull request overview

This PR tightens device protocol correctness across MQTT command payloads, queued command handling, and multiple encoding/decoding edge cases, with a new regression test suite to lock in the intended on-wire behavior.

Changes:

• Fix schedule command payloads to send flat lists of raw protocol entries (via NavienBaseModel.to_protocol_dict()), avoiding double-nesting and computed/display-field leakage.
• Rework MQTT command queue flushing to preserve ordering on failure and to discard stale queued commands based on MqttConnectionConfig.max_queued_command_age.
• Correct protocol encoding/decoding edge cases (negative ASYMMETRIC Fahrenheit rounding, freeze protection raw defaults, error-change event emission, TOU price encoding rounding/bool handling) and document them.

Reviewed changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
tests/test_protocol_correctness.py	Adds targeted regression tests for protocol payload shapes, queue ordering/expiry, temperature rounding, defaults, events, and TOU price encoding.
src/nwp500/_base.py	Introduces to_protocol_dict() to dump only declared fields (by alias) for device-bound payloads.
src/nwp500/mqtt/control.py	Updates schedule-related commands to send flat raw protocol entries rather than dumping full models.
src/nwp500/mqtt/command_queue.py	Switches queue to deque, preserves order on failed flushes, and adds send-time expiry logic.
src/nwp500/mqtt/utils.py	Adds max_queued_command_age config field (used by the queue expiry behavior).
src/nwp500/mqtt/state_tracker.py	Emits error_detected when the error code changes between non-zero values.
src/nwp500/temperature.py	Fixes ASYMMETRIC rounding for negative raw values and updates doctest expectations.
src/nwp500/models/status.py	Corrects freeze protection default raw values to match documented limits.
src/nwp500/encoding.py	Implements HALF_UP TOU price rounding and prevents bool from silently passing as pre-encoded int in TOU builders; fixes protocol docs/examples.
CHANGELOG.rst	Documents the protocol correctness fixes under Unreleased.