feat(myuplink): improve NIBE F750 telemetry

[segran2]

Summary

Improve NIBE F750 telemetry using parameter data observed on real F750 hardware through MyUplink Cloud API v2.

The change:

• corrects parameter 40013 documentation to BT7 hot-water top temperature
• exposes parameter 40940 as canonical hp_degree_minutes
• ignores NIBE's -32768 unavailable-value sentinel instead of emitting bogus telemetry
• removes embedded U+00AD soft hyphens from generated metric names
• adds an F750 regression test based on hardware-observed parameter data

No F750 electrical compressor-power mapping is added. Parameter 10012 was not present in the hardware capture, so the driver does not infer electrical power from unrelated parameters.

Driver evidence

• Driver id: myuplink
• Device make/model: NIBE F750
• Firmware tested: hardware-tested F750 via MyUplink Cloud API v2
• Protocol/register source: MyUplink Cloud API v2 /v2/devices/{deviceId}/points
• Hardware test performed: Yes — live F750 telemetry captured and used to build the regression fixture
• Known limits: No verified F750 electrical compressor-power parameter was observed; no hp_power_w mapping is claimed for F750

Observed parameters include:

• 40004 — BT1 outdoor temperature
• 40013 — BT7 hot-water top temperature
• 40033 — BT50 room temperature
• 40940 — current degree-minute value (DM)
• 41778 — current compressor frequency
• 43084 — internal additional-heat power
• -32768 — unavailable-value sentinel observed on multiple points

Safety

• The driver starts read-only, or this is a separately reviewed control change.
• Vendor signs are converted at the driver boundary.
• Cached telemetry becomes stale instead of being re-emitted as fresh.
• No credentials, serial numbers, private addresses or site data are included.

The driver remains read-only. This PR adds no control/write path.

Control evidence

Not applicable — read-only telemetry change.

• HIL evidence or required: not applicable
• Control changes: not applicable; no control path changes.

Checks

• Commits include Signed-off-by.
• make test-driver ID=myuplink
• make check

Full make check: 4810 passed, 923 skipped.

All 91 drivers passed the sandbox safety check. Manifest, index, devices and support-status generation are clean. FTW baseline and host API checks also passed.

[miravoss26]

Mira's read (pr-steward sweep). 2-line summary: MyUplink F750 telemetry. BT7 relabel, degree-minutes as a canonical metric, the -32768 sentinel is ignored, and soft hyphens are stripped from metric names. The driver stays read-only (control: false unchanged).

Checks: the size (18431) and sha256 pinned in index.yaml and manifests/myuplink.yaml match the driver file at this head. The new harness test covers the F750 payload, including the sentinel and soft-hyphen cases.

Findings:

• [low] decode_temp used to emit 0 for a missing value and now emits nothing. That's the intent, but it changes what dashboards see for an absent point. Worth one changelog line.

Security screen: no secrets, no new hosts or endpoints.

Safe to merge from my read. Not auto-merge eligible (repo not on the POLICY allowlist), so a human merges.