Reformat BibTex in Show BibTex Source

[harii55]

Closes #13015

Reformats the BibTeX shown in the Import dialog’s “Show BibTeX source” preview to JabRef’s canonical style. The incoming string is parsed into a BibEntry and rendered via BibEntryWriter with reformat=true; if parsing fails, the raw string is shown unchanged. This makes the preview readable and consistent with JabRef’s formatting guidelines.

Steps to test

1.Open JabRef
2.Create new library
3.Open Firefox
4.Ensure that JabRef plugin is installed
5.Navigate to https://learning.oreilly.com/library/view/infrastructure-as-code/9781098150341/
6.Click on "Import references..."

7.See Popup

8.Select "Show BibTeX source"
9.See the formatting

Before :

After :

Mandatory checks

• I own the copyright of the code submitted and I license it under the MIT license
• I manually tested my changes in running JabRef (always required)
• [/] I added JUnit tests for changes (if applicable)
• I added screenshots in the PR description (if change is visible to the user)
• I described the change in CHANGELOG.md in a way that is understandable for the average user (if change is visible to the user)
• Checked developer's documentation: Is the information available and up to date? If not, I outlined it in this pull request.
• Checked documentation: Is the information available and up to date? If not, I created an issue at https://github.com/JabRef/user-documentation/issues or, even better, I submitted a pull request to the documentation repository.

[Siedlerchr]

You can also trigger this import window when you use the Web search e.g. arxiv or similar

[Siedlerchr]

No need to close and reopen every time, this creates unnecessary noise

[koppor]

Looks good; just CHANGELOG.md entry missing.

---

Tested using

"Web search"

[koppor]

I added the CHANGELOG.md entry for myself to keep things going.

[jabref-machine]

Note that your PR will not be reviewed/accepted until you have gone through the mandatory checks in the description and marked each of them them exactly in the format of [x] (done), [ ] (not done yet) or [/] (not applicable).

[trag-bot]

@trag-bot didn't find any issues in the code! ✅✨