Documentation release.
- List the full supported Helty Flow model line using official branding: FlowPLUS, FlowULTRA, Flow40, Flow120, FlowMANHATTAN.
- Clarify that the integration was verified live on a FlowPLUS; the other models share the same smart Wi-Fi interface and are expected to be compatible.
- Link to the official site (heltyair.com).
No functional changes since v0.2.0.