fix: measureData returns no data on AP/SG v1 API due to missing deviceModel and lossy MAC-derived serial

[tlvu2697]

Problem

On the AP/SG v1 API, sync/get_measurements reports "No measurements found" for a valid, correctly registered device — even with a wide date range and correct device/user selected. The account authenticates fine, omron list finds the device correctly; the measurement query just always comes back empty.

Root cause

Two independent bugs in OmronConnect1.get_measurements() combine to make the Kii measureData call always return deviceModelList: null:

1. Missing deviceModel in the request body. The backend silently requires it to route the query — omitting it always yields an empty deviceModelList: null, even for an otherwise-correct request. This was confirmed by capturing traffic from the official app, which always sends this field (there's even a comment in the existing code noting the field exists, but it was never actually included: # "deviceModel": "OGSC", "HBF-xxx", ...).

2. Lossy MAC↔serial round-trip. Kii's real deviceSerialID is 8 bytes, but serial_to_mac() (used when storing a device from get_registered_devices) only encodes 6 of those bytes into the MAC address, discarding the last two. ble_mac_to_serial() — used to reconstruct the serial for the query — can't recover those discarded bytes, so it produces a serial that doesn't match the real one on accounts/devices where those trailing bytes aren't the assumed fixed pattern. The query then targets a device ID that doesn't exist, so it correctly (from the server's point of view) returns nothing.

Fix

• Send deviceModel in the measureData request body, derived from OmronDevice.name (always stored as "<deviceModel>:<userNumberInDevice>", so no schema change is needed to get it).
• Add an optional real_serial field to OmronDevice. get_registered_devices() now populates it with the server's actual deviceSerialID, and the serial property prefers it over the reconstructed value. Devices without it (e.g. added manually via add --macaddr, or added before this fix) keep falling back to the existing ble_mac_to_serial() derivation, so this is backward compatible with existing config files.

Verification

[tlvu2697]

Hi @bugficks,

I was unable to pull weight data on my account (AP/SG region) - sync always reported "No new measurements" regardless of date range. With Claude's help I diagnosed and fixed it (see PR description for the full root-cause writeup), and I've confirmed it now works end-to-end on my own account.

I don't have much background in Python or the OMRON APIs myself, so I'd really appreciate it if you could take a look and let me know if the approach looks right, or if there's a better way to fix it.

Thanks for maintaining this project!