Add SPH device support via the regional mobile API

[morland96]

Summary

Newer SPH/SPM hybrid inverters (e.g. SPM-10000TL-HU) aren't reachable via the existing legacy mix_/tlx_/storage_* endpoints — those return null/zero values. They're also not reachable via the V1 sph_* methods because V1's device_list omits these devices entirely.

I proxied my phone and looks like ShinePhone mobile app to reverse engineer the same set of methods for SPH/SPM inverters:

• sph_system_status(plant_id, sph_sn) — real-time SOC, vBat, PV (per-string), battery charge/discharge, grid in/out, local load, AC voltage/frequency
• sph_energy_overview(plant_id, sph_sn) — daily and lifetime kWh totals
• sph_energy_prod_and_cons(plant_id, sph_sn, date, chart_type) — chart series (day/month/year/total)
• sph_settings(sph_sn) — full settings bean (149 adjustable parameters on this device)
• update_sph_inverter_setting(serial, type, params) — write a setting via newTcpsetAPI.do?op=sphSet

An exampled is included: examples/sph_legacy_example.py

Checklist

• I've made sure the PR does small incremental changes. (new code additions are dificult to review when e.g. the entire repository got improved codestyle in the same PR.)
• I've added/updated the relevant docs for code changes i've made.

[johanzander]

Overall this looks good — clean, well-scoped, follows existing patterns (tlx_, mix_), and fills a real gap for newer SPH/SPM models that aren't reachable via V1 or the legacy mix/tlx/storage endpoints.

One thing I'd like the repo owner to weigh in on:

The change on line 90 of base_api.py switches __get_date_string from datetime.datetime.now(datetime.UTC) to naive datetime.datetime.now(). The reasoning in the comment is sound (Growatt interprets the date string in the plant's local timezone), but this is a behavioral change for all existing callers (e.g. plant_detail, mix_detail, tlx_energy_prod_cons), not just the new SPH methods. Users who were relying on the UTC default could see different results near midnight.

@indykoning — are you OK with this change to the shared __get_date_string default, or should we keep UTC there and only use local time in the new SPH-specific date handling?

[johanzander]

One more thing: could you add type annotations to the new SPH methods? The rest of the codebase on master has them.

[indykoning]

The reasoning in the comment is sound (Growatt interprets the date string in the plant's local timezone), but this is a behavioral change for all existing callers (e.g. plant_detail, mix_detail, tlx_energy_prod_cons)

I agree with this, though it could be a bug i introduced when adding and running ruff:
c754b8f#diff-3da34889a61a85f5b4f4bf8ab496d0474ff3353036f3ab4ac2ddeefdb951247fR84

If we could double check that e.g. the https://github.com/indykoning/PyPi_GrowattServer/blob/master/growattServer/base_api.py#L200 plant_detail function also uses the localized date instead of UTC my worries will have been taken care of.