chore: more flexible requirements.txt build + Python 3.14 support (maybe)

[nkemnitz]

• more flexible requirements.txt build allows targeting multiple Python versions
• bypass installing the unused (and outdated/unmaintained) sub-dependencies of cutie
• remove hard pins from cloud-volume/cloud-files - we have uv for that.

Python 3.14 support "maybe": Other than pip, uv ignores packages requires_python upper bound, arguing that most packages still work fine on new Python versions and maintainers are just overly careful (or the package is abandoned)... In this case, at least imaug is currently missing a flag for 3.14... tests are passing, but who knows.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 99.98%. Comparing base (aa63a57) to head (bc2fc5f).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1255   +/-   ##
=======================================
  Coverage   99.98%   99.98%           
=======================================
  Files         206      206           
  Lines       10914    10920    +6     
=======================================
+ Hits        10912    10918    +6     
  Misses          2        2           

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