feat: Show accurate posting times in check-in headers

[Rockyy174]

Fixes #2522.

[sourcery-ai]

Hey - I've left some high level feedback:

• Consider tightening the CheckInTimestamp type (e.g., preferring Date at the boundaries) or validating at the call sites, since parseCheckInTimestamp currently throws on invalid strings and this could surface as runtime errors if any caller passes an unexpected value.
• The conditional styling in CheckInMetadata based on resourceType is starting to get a bit complex; splitting goal and project variants into small wrappers or using a style map could make the layout differences easier to follow and maintain.

Prompt for AI Agents

Please address the comments from this code review:

## Overall Comments
- Consider tightening the `CheckInTimestamp` type (e.g., preferring `Date` at the boundaries) or validating at the call sites, since `parseCheckInTimestamp` currently throws on invalid strings and this could surface as runtime errors if any caller passes an unexpected value.
- The conditional styling in `CheckInMetadata` based on `resourceType` is starting to get a bit complex; splitting goal and project variants into small wrappers or using a style map could make the layout differences easier to follow and maintain.

---

Sourcery is free for open source - if you like our reviews please consider sharing them ✨

• X
• Mastodon
• LinkedIn
• Facebook

_{Help me be more useful! Please click 👍 or 👎 on each comment and I'll use the feedback to improve your reviews.}