feat: add Freshping uptime monitoring provider

[selenaalpha77-sketch]

Summary

Adds a new provider for Freshping by Freshworks, a website and API uptime monitoring service. Freshping checks availability from multiple global locations and alerts teams when checks go down or recover.

• Webhook-based provider: receives real-time alerts when Freshping checks become unavailable or recover
• Map Freshping check_status values (unavailable, available, unknown) to Keep severities and alert statuses
• Optional webhook secret token support for payload signature validation
• Full alerts_mock.py for webhook payload testing
• MDX documentation with step-by-step setup for configuring webhook alert contacts in Freshping

Note: Freshping does not expose a public REST API for polling check status, so this provider operates exclusively via webhooks. validate_scopes always returns true since there is no API endpoint to validate against.

Provider files

• keep/providers/freshping_provider/freshping_provider.py
• keep/providers/freshping_provider/__init__.py
• keep/providers/freshping_provider/alerts_mock.py
• docs/providers/documentation/freshping-provider.mdx

Test plan

• Send a test webhook payload matching alerts_mock.py and verify _format_alert produces a correct AlertDto
• Verify check_status: "unavailable" maps to FIRING / CRITICAL
• Verify check_status: "available" maps to RESOLVED / INFO
• Verify check_status: "unknown" maps to FIRING / WARNING

🤖 Generated with Claude Code

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