feat(dashboard): order fridge monitor cryostat levels by temperature

Summary

• Follow-up to !477 (merged): since the fixed cryostat-level vocabulary was removed, plot order followed raw declaration order in system-monitor-dashboard.toml, which is arbitrary.
• Numeric level names (e.g. 50K, 4K, 800mK) are now parsed and sorted hottest to coldest by their approximate temperature in mK.
• Still is placed via a fixed canonical point (~700mK) between the 3K/4K stage and sub-Kelvin stages; MXC/MC/Mixing Chamber aliases always sort last, as the coldest point in the fridge.
• Level names that don't match any of the above keep their original declaration order and are appended after all recognized levels.

Test:

Config:

thermometry_component_id = "thermometry_unit_1"

[thermometers]
thermometer_1 = "3K"
thermometer_2 = "4K"
thermometer_3 = "4K"
thermometer_4 = "Any name"
thermometer_5 = "3K"
thermometer_6 = "Mixing Chamber"
thermometer_7 = "MXC"
thermometer_8 = "50K"
thermometer_9 = "More rows"
thermometer_10 = "24K"
thermometer_11 = "24mK"
thermometer_12 = "300K"
thermometer_13 = "Still"
thermometer_14 = "still"
thermometer_15 = "800mK"
thermometer_16 = "600mK"

Output:

Closes #406 (closed)