Refactor heating control to cycle-centric architecture

[Alexwijn]

Summary by CodeRabbit

• New Features

  • Areas UI with per-room weights; per-room PID sensors, requested-setpoint sensor, and Maximum Setpoint number entity.

• Improvements

  • Cycle-based diagnostics with start/end events and history; richer boiler status and persistence; dynamic regime-aware minimum-setpoint tuning; revamped PID/PWM/heating-curve control; stronger overshoot protection, stale-temperature handling, clearer availability and naming across sensors.

• Removals

  • PWM management service, legacy flame health, relative-modulation feature, and setpoint adjuster modules.

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