Feature request: webhook triggers on virtual pin change

Request: Outbound webhooks from dashboard

**Use case:** I want Plynx to call a webhook URL whenever V3 goes above a threshold, so I can trigger a Home Assistant automation without polling.

Proposed API

123456789{  "trigger": "pin_threshold",  "pin": "V3",  "condition": ">",  "value": 75.0,  "webhook_url": "https://ha.local/api/webhook/plynx",  "method": "POST",  "payload_template": "{\"pin\": \"{{pin}}\", \"value\": {{value}}}"}

This would unlock native Home Assistant integration without a broker in between.