v0.2.2

Changes

• Add multi-meter support with backward-compatible entity IDs for existing single-meter users
• Add PSEUDO_METER_ID sentinel constant replacing the "default" magic string
• Services now raise a validation error when multiple meters are present but no meter_id is given
• Meter IDs no longer include an underscore separator (e.g. 1308911499 instead of 13089_11499)
• Move device info logic to sensor layer (coordinator no longer owns UI concerns)
• Update README with accurate HA entity ID examples for both single- and multi-meter setups
• 100% test coverage, all lint checks pass