Statuspage.io integration for Uptime Monitoring

### Problem Statement

There's currently no way to connect Sentry Uptime directly to Atlassian Statuspage to automatically update component statuses when downtime is detected or recovered. Most competing uptime tools (Better Stack, UptimeRobot, etc.) offer this out of the box. For teams running public status pages, this is a critical gap.

### Solution Brainstorm

A native Statuspage.io integration for Uptime Monitoring, similar to what exists for Slack and PagerDuty, that can map uptime monitors to Statuspage components and auto-update their status on outage and recovery.

Original ticket [here](https://sentry.zendesk.com/agent/tickets/174648).

### Product Area

Settings - Integrations

Start in Settings - Integrations by reviewing the existing Slack and PagerDuty integrations. Define how uptime monitors map to Statuspage components and how outage and recovery events update component statuses; done means the integration supports both automatic transitions.

Written by the indexing model from the issue text.