chore: Drop Python 3.9 support, advertise 3.14

[effigies]

Python 3.11 is now out of SPEC0 support. Also bumps minimum dependencies in accordance with #803.

[codecov[bot]]

Codecov Report

:white_check_mark: All modified and coverable lines are covered by tests. :white_check_mark: Project coverage is 95.43%. Comparing base (0f61bcb) to head (23addf0).

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #1448   +/-   ##
=======================================
  Coverage   95.42%   95.43%           
=======================================
  Files         209      209           
  Lines       29814    29807    -7     
  Branches     4483     4483           
=======================================
- Hits        28451    28446    -5     
+ Misses        930      926    -4     
- Partials      433      435    +2     

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.

:rocket: New features to boost your workflow:

• :snowflake: Test Analytics: Detect flaky tests, report on failures, and find test suite problems.