v1.4.0-beta.1 — appliance status, decoded 🔥🩺

Opens the 1.4.0 line with #18 from
@jfhautenauven. Pre-release — the headline feature is transcribed from manufacturer
documentation rather than observed against a live boiler, so it ships on its own version
number until someone runs it.

POINTTAPI (cloud / EasyControl) path only. The XMPP/HTTP path is unchanged.

Appliance status, in words

/system/appliance/displayCode and causeCode are two opaque numbers. They are now resolved
against a Bosch/Buderus display+cause table into a readable state — heating_operation,
no_flame_after_ignition, supply_temp_too_high — with the raw codes kept on the entity
attributes so nothing is lost. Locking and blocking faults take precedence over the normal
status.

Ambiguous causes deliberately read unknown. Cause 273 is a 24-hour safety shutdown under
display 3F but ordinary flame monitoring under 0U; 280 is a restart-time fault under 7L
but a normal fan start under 0U. A cause code arriving without its display code cannot tell
those apart, and a boiler that is simply lighting up should not announce a safety shutdown to
whatever notification you wired up.

Also new

• Per-zone assigned-program selects — the zone's schedule is writable now, by decoded name.
• Per-zone optimum start state, where the zone advertises it.
• Heat demand type — off / central heating / hot water.
• Conditional entity creation — zigbee firmware, electricity annual goal, energy efficiency
  and the annual gas goal appear only when your gateway actually advertises them. Fewer
  permanently-unavailable entities on gateways that never had those resources.
• Electricity day/month averages in kWh, as plain informational sensors — no device_class
  or state_class, so they stay out of long-term statistics until someone confirms they
  accumulate.

Fixed

• Thermal disinfect switch read as off while running — the path speaks on/off, not
  true/false.
• Burner flame now derives from actualModulation instead of parsing flameIndication,
  whose off/ch/dhw dialect an on/off parser cannot read.
• Valve zone shows the room name instead of the zone number; battery ok reads OK.

Changed

• Zone climate preset control removed. AUTO and HEAT already write the same userMode,
  so the preset was a second control for one setting.
• Energy efficiency sensor moved to the Energy performance device.

Testing this

Anything touching the appliance status sensor is the useful report: whether the state matches
what your boiler's own display says, especially during startup and hot-water cycles. If you see
unknown alongside a display_code in the attributes, that pair is missing from the table and
is worth posting.

Full notes in CHANGELOG.md.
Cleanup follow-ups tracked in #19.