Add ST CUBE WIFI WM 100L W 2400W (1983) and FLAT/S4 IOTHUB (1763) support

[Joonel]

Summary

• Model definitions for the ST CUBE WIFI WM 100L W 2400W water heater (modelId 1983) and its FLAT/S4 IOTHUB DEFAULT hub (modelId 1763)
• Distinct names for the ST CUBE's five temperature setpoints (manual, eco+, percentage-based, eco, auxiliary) instead of five colliding target_temperature entities — model-gated, other models unchanged; EN/FR translations included
• Caps 105906/105907 max raised 65 → 70 °C to match what the hardware actually accepts (device reports setpoints up to 70 °C)
• New optional v40WaterAvailable model flag to skip cap 268 per model: the ST CUBE always reports 0 for it, so the entity was pure noise. Defaults to True, other models unaffected.

Testing

Running in production on real hardware (ST CUBE + FLAT/S4 hub) since February 2026.

🤖 Generated with Claude Code

https://claude.ai/code/session_01635y2ipTY7KdjuMDvqbDtH

[Dasert75]

Same device, different modelId: my unit reports 1984, not 1983.
Commercial name is identical (ST CUBE WIFI WM 100L W 2400W), and the hub
comes up as 1763 exactly as in this PR — so it looks like a variant of the
same product, similar to KELUD already being listed under 1381 and 1382.

I ran this branch with a one-line widening of the model gate:

# model.py
elif modelId in (1983, 1984):

# capability.py — same change in all four places
if modelId in (1983, 1984):

Results on my unit:

• device is now recognised as a water heater instead of Unknown product (1984)
• Heating Mode select works: Manual / Eco+ / Prog
• the colliding target_temperature entities are properly split — I get
  distinct Eco+ and hot-water setpoints instead of several identically
  named ones
• cap 268 is correctly skipped: it reported Unknown here before, so the
  v40WaterAvailable flag does the right thing

Would you consider adding 1984 to the same branch? Happy to open a separate
PR against your branch if you prefer.