feat: migration guide updates

[unatasha8]

Review draft of updated Migration guide articles (includes sidebar nav changes).

• DOCS: Migration guide research & planning #9211
• https://docs.google.com/document/d/1c6RT02Y8JuZL4InmU7C7F5pUZH56nHOVOXyDoTyMfPA/edit?pli=1&tab=t.0#heading=h.aw5hspe5kjpj
• https://docs.google.com/document/d/15jJD-vb9AM_2OCdAZAUe-9lZzD5EiK6Pgggs-LS0ubw/edit?pli=1&tab=t.0#heading=h.fl2670d0txa3
• https://docs.google.com/document/d/1-vE3wOP4tVF49tlsNCnGshMWNsYkFZ_8zGQadtMcDnM/edit?tab=t.0

Checklist

• I have read the contributing guidelines and signed the CLA.
• I have referenced an issue containing the design document if my change introduces a new feature.
• I have read the security policy.
• I confirm that this pull request does not address a security vulnerability.
  If this pull request addresses a security vulnerability,
  I confirm that I got approval (please contact security@ory.sh) from the maintainers to push the changes.
• I have added tests that prove my fix is effective or that my feature works.
• I have added the necessary documentation within the code base (if appropriate).

Further comments

[jhickmanit]

Will this go live like this or will the language be more generic?

[unatasha8]

Will this go live like this or will the language be more generic?

No, this is more of a place holder for next iteration when we have more info to add to this section.

[jhickmanit]

Should we also include a call out to the Event Stream as another way to potentially integrate backends like Ory Actions? It may get more eyes on the feature.

[unatasha8]

Should we also include a call out to the Event Stream as another way to potentially integrate backends like Ory Actions? It may get more eyes on the feature.

Perhaps in the future. I'm not familiar with that functionality just yet.

[jhickmanit]

I think we need a few more examples for this table, but that I think is on us in the Field. Let me noodle on this a bit.