fix magic.bibliography-as-footnote in typst 0.14

[AngelPone]

This pull request fixes magic.bibliography-as-footnote (#229) through the following fixes:

1. extract the bibliography using cite(<key>, form: full)
2. use regex to remove [1] at the beginning of rendered citation.
3. record the bibitem everytime a new key is visited.
4. reuse the footnote if some item is cited multiple times in one subsection.

Based on this new mecanism, the state bibliography-map and bibliography-counter, and the argument record will be unnecessary and thus are removed.

[jhalmen]

I'd tried this quickly last week, and the footnote citations only appear on the first sub-slide when using animations i.e. #uncover and family

[AngelPone]

@jhalmen I've pushed some changes to address this issue, and it should now be resolved in most scenarios.

However, during testing, I noticed a couple of edge cases that seem to be outside the scope of this PR:

1. Footnote visibility with animations: Citations appear in the footnotes immediately, even if the #cite has not yet been revealed. For example:

- Item 1 @some-key  #pause
- Item 2 @another-key

On the first slide, only the bibliography entry for Item 1 should be visible. However, entries for both @some-key and @another-key are displayed. This seems to be related to how Touying handles animation internally.

2. Page overflow with animations: When content is long enough to overflow to a second page, combining this with animation can sometimes result in blank pages.

Note: Both issues were also present in the old bibliography-as-footnote implementation (pre-Typst 0.14.0), so they are likely pre-existing issues rather than regressions introduced by this PR.