Improve Display-Modbus init progress

[dosordie]

Motivation

• The Display-Modbus "Alle Register abfragen" flow is a multi-step, interactive sequence (trigger bits, wait for response, evaluate, next step) that was not represented accurately in the main init progress UI.
• The goal is to show the real Display-specific sequence in the existing progress bar/status label without changing communication, parsing, capture or functional Display logic.

Description

• Added lightweight progress callbacks in the Display init controller: DisplayKnownReadController._progress, _busy, _finished, _failed and wired them at key points (prepared, worker start, trigger/send, wait, response, retry rounds, timeouts) in workers/display_worker.py to report Display-Modbus steps.
• Exposed progress handlers on the main window: display_init_progress_changed, display_init_progress_busy, display_init_progress_finished, display_init_progress_failed and adjusted _init_read_progress_counts / _update_init_read_progress in foxair_phnix_control.py so the existing init_progress_bar and status_label reflect Display-Modbus deterministic steps and busy/indeterminate waiting (uses setRange(0,0) for busy phases and switches back to deterministic ranges when available).
• Added simple progress bookkeeping fields display_known_init_progress_done and display_known_init_progress_total and incrementing logic so the progress bar advances only on real events (trigger sent, response received, block processed, retries), not timers.
• Propagated Display write step status into relevant editor dialogs by adding _notify_timer_sg_write_status and calling it from the Display timer/SG write flow (_display_timer_batch_send_current_step, _display_timer_batch_check_step_ack) so editor status_labels show step sent / ACK / 0BC3-confirm / optional-ACK warning / failure, without changing write semantics.
• All changes are UI/progress/status wiring only; no protocol, parser, capture, cloud, Warmlink, firmware-logging, or write semantics were altered.

Testing

• Ran python -m compileall . and compilation succeeded.
• Ran PYTHONPATH=. pytest and automated test suite passed: 16 passed, 2 skipped.
• No hardware/manual smoke tests were run in this environment (manual Display-Modbus UI smoke test recommended on device: progress bar visible, statuses for trigger/wait/response/processing/finish and no busy hang).

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