## Overview
This PR implements several fixes and enhancements requested in the latest session:
### Fixes
1. **Issue 1: Raw Email Headers**
- Added database support for raw headers.
- Added a new Headers tab in the email detail screen with a zebra-colored table display.
2. **Issue 2: Exception on Undo of Delete**
- Added `toJson` and `fromJson` to `EmailAddress` model to fix serialization during undo.
3. **Issue 3: Crash Reporting**
- Added a button to the Crash Screen to report issues directly on Codeberg.
### Infrastructure
- Added Nix experimental features check to `Taskfile.yml` to ensure a consistent dev environment.
## Verification
- Manually verified the Headers display on Linux.
- Verified Undo for IMAP and JMAP accounts.
- Verified the Crash Screen button.
Co-authored-by: Thomas SharedInbox <sharedinbox@thomas-guettler.de>
Reviewed-on: https://codeberg.org/guettli/sharedinbox/pulls/6
