new "cp_revealed" state doesn't have human-friendly text

[lsabor]

the new status "cp_revealed" was added recently, but lacks support for human-friendly readability.

image content: this is a quote from an email (I think) notification that says:

These 2 questions have changed status:

Which Party will win the 2026 Gorton and Denton by-election?
is now cp_revealed
[remaining content cropped]

@claude this might be a quick fix, can you do it?

[claude]

Claude finished @lsabor's task in 4m 1s —— View job • claude/issue-4281-20260208-1608 • Create PR ➔

---

Tasks

• Gather context and understand the request
• Find where question statuses are mapped to human-friendly text
• Add human-friendly text for cp_revealed status in email templates
• Commit and push changes

Summary

The issue was that {{ notification.event }} in the email templates rendered the raw enum value "cp_revealed" directly (since asdict() serializes Django TextChoices enums to their string value).

Fix: Added a post_status_label template filter in misc/templatetags/utils.py that converts raw status values to their human-friendly labels using Post.PostStatusChange(value).label. Updated both the .html and .mjml email templates to use {{ notification.event|post_status_label }} and {{ item.event|post_status_label }}.

Now "cp_revealed" will display as "CP Revealed", and other statuses like "open" → "Open", "closed" → "Closed", "resolved" → "Resolved" as well.