fix: check for bracketed paste mode in input handler

[eexwhyzee]

i'm using ghostty-web in an experimental jupyter lab extension to replace its built-in terminal, and noticed that the bracketed paste was not working correctly.

I looked into the input handler code and saw that the fix is pretty much noted in the existing doc string haha so this PR just updates the input handler to check if bracketed paste mode is enabled, if so, wrap the text in the paste sequences.

Testing

i tested a local build of ghostty-web with my jupyter lab extension and it was working as expected, i also ran the demo locally to confirm the fix as well

before the fix:

after the fix:

[sreya]

Thanks for this!