[Feature] Public incident history with status tags on status page

### Summary
Add a visible incident history section to the public status page where administrators can communicate incident status and resolution progress to end-users.

### Problem
Currently, incident history is only visible in the admin dashboard. End-users checking the status page have no way to see past incidents or understand what's being done to resolve current issues.

Proposed Solution
Add an incident history section at the bottom of the public status page with:

- Timeline of past incidents
- Status tags for each incident:
```
Investigating
Working on a fix
Resolved
```
- Ability to attach messages/updates explaining how issues are being resolved
- Timestamps for each status change
- Mockup Reference
- Similar to other status page providers:

Incident History Example

Incident Detail Example