Move power status value interpretation from hardcoded logic to OID set configuration.
Each UPS model now defines its own value mappings (e.g., CyberPower: 2=online, 3=onBattery).
Fixes incorrect status display where UPS showed "On Battery" when actually online.
Changes:
- Add POWER_STATUS_VALUES to IOidSet interface
- Define value mappings for all UPS models (cyberpower, apc, eaton, tripplite, liebert)
- Refactor determinePowerStatus() to use OID set mappings instead of hardcoded values
- CyberPower now correctly interprets value 2 as online (was incorrectly onBattery)
- Created deno.json configuration
- Updated all imports to use npm:net-snmp@3.20.0
- Changed all Node.js built-in imports to node: specifiers
- Updated all .js extensions to .ts in imports
- Created mod.ts as Deno entry point
- Ready for Phase 3: CLI simplification
