fix: Update children age limits and rules

[MoritzWeber0]

Update all children sections. For many operators, there is only 50% discount for children on the public fares, so we can say that they pay the full FIP fare (which is also 50%). This makes more sense in general, as in other places we don't list public fares either.

Many pages also had really outdated age limits, I tried to research the current limits for all operators using their websites.

Resolves #920
Resolves #685
Resolves #750

[github-actions]

Hi there! 👋

Thank you for your contribution to the FIP Guide! 🚀
We appreciate your effort in making rail staff travel information more accessible. 🚄

Checklist before merging:

• Added a description to the Pull Request
• Checked the License of new pictures (non-commercial use without attribution)
• Modified content in English
• Modified content in German
• Modified content in French

[netlify]

✅ Deploy Preview for fipguide ready!

Name	Link
🔨 Latest commit	c4fb18c
🔍 Latest deploy log	https://app.netlify.com/projects/fipguide/deploys/6a370318dc93130008b01740
😎 Deploy Preview	https://deploy-preview-1016--fipguide.netlify.app
📱 Preview on mobile	Toggle QR Code... Use your smartphone camera to open QR code link.
🤖 Make changes	Run an agent on this branch

---

To edit notification comments on pull requests, go to your Netlify project configuration.

[MoritzWeber0]

How should we handle these cases?

• The FIP discount for children is higher than the public fare. Should we still list the public fare?
• The public fare is cheaper than the FIP fare? Should we still list the FIP fare?
• But fares (public and FIP) give 50 % discount. Which one should be mention? Both?

I'm also open to any ideas how to visualize it. I thought about something like this, but the FIP discount is always the same (independent of the age), so the visualization doesn't make much sense: