Feature Request: Full Incident Management for Status Pages

Current status pages in Checkmate are limited to automatically showing Degraded performance when a monitor detects an issue.
Internal incidents exist, but they cannot be synced properly to the public status page (#3006), they lack detail, and they can be resolved silently without updates.

Compared to tools like Better Stack Status (https://neuland.betteruptime.com), Atlassian Statuspage (https://jira-software.status.atlassian.com), and Instatus (https://status.instatus.com), Checkmate’s incident communication is still very basic. I personally find Better Stack’s layout and incident timeline the most intuitive.

What I Personally Need

1. Manual Incidents

Support for creating manual incidents with:
title, summary, description (markdown), severity/impact, affected monitors, visibility (public/internal).

2. Updating Incidents

Ability to post update entries with states such as:
investigating, identified, monitoring, resolved, custom.

Updates should appear as a chronological timeline on the public status page.

3. Incident History / Timeline View

A proper history on the status page:

• day‑grouped incident history (similar to Better Stack)
• incidents shown individually when multiple are active
• expandable entries showing all timeline updates

4. Public Status Page Improvements

• replace the single generic message with real incidents + labels
• support multiple active incidents
• clear status summary based on severity labels

5. Interaction With Monitors

• option for monitors to auto‑create an incident
• auto‑resolve only if the incident has no manual updates (configurable)

Example Use Cases

• A degradation that monitors do not detect → I want to manually create an incident and post updates.
• A failing monitor should create a proper public incident with a severity label.