fix: refuse importing/saving user configs newer than Agent or firmware

[mondalaci]

Summary

• Closes [low priority] Userconfig versions - Agent allows flashing higher config versions. #2784
• Block importing a user configuration whose major/minor version is newer than Agent’s built userconfig (same shouldUpgradeAgent policy already used when loading from the device)
• Block importing (and saving) a user configuration newer than the connected firmware’s userConfigVersion (firmwareBuiltUserconfig), with version numbers in the error

Test plan

A. Import of newer config than Agent is refused

1. Build/run this Agent (current userConfigVersion, e.g. 15.0.0).
2. Take a UserConfiguration.json and bump userConfigMinorVersion (or major) so the semantic version is newer than Agent’s built userconfig (e.g. 15.1.0 if Agent is 15.0.0).
3. Device → Configuration → Import from file.
4. Expected: Error like: The imported user configuration version (15.1.0) is too high for this Agent (supports up to 15.0.0). Please update Agent. — config is not applied.
5. Confirm a same-or-older version JSON still imports normally.

B. Import above firmware capability is refused

Use --disable-agent-update-protection so guard A does not block the import:

1. Note the connected firmware’s userConfigVersion (device info / logs).
2. Start Agent with --disable-agent-update-protection.
3. Import a configuration whose version is strictly greater than that firmware userconfig version (and that Agent can otherwise peek).
4. Expected: Error like: The imported user configuration version (X.Y.Z) is too high for this firmware (supports up to A.B.C). Please update the firmware or use a compatible configuration. — not Invalid configuration specified.
5. Optional: if a too-new config somehow gets into memory, Save to keyboard still shows the same firmware version comparison.

C. Regression — normal path still works

1. With matching Agent + firmware + config versions (typical daily use), import a same-version export and Save to keyboard.
2. Expected: Import and save succeed as before.
3. Optional: load config from device that is newer than Agent → still routed to Update Agent (unchanged device-load path).

D. Unit tests

cd packages/uhk-common && npm test

Confirm isUserConfigVersionHigherThanFirmware / readUserConfigurationVersion* cases pass.