fix(worker): configure logging in forkserver worker processes

[t-cas]

Closes #685

Worker processes only reconfigured logging when the start method was spawn. A forkserver child also starts from a fresh interpreter, so it inherited nothing and logged nothing: no Listening started., no shutdown messages. forkserver is the default start method on Linux since Python 3.14.

• The logging setup moves to a small configure_child_logging(args) helper, called from start_listen. It configures logging for every start method except fork, the only one that inherits the parent's configuration.
• New tests in tests/cli/worker/test_child_logging.py cover spawn and forkserver, fork, and --no-configure-logging.

I ran the reproduction from #685 against this branch on Python 3.14.7. worker-0 now logs Listening started. once with each of fork, spawn, forkserver and the default. prek run -a and pytest -n auto pass locally.

[codecov]

Codecov Report

❌ Patch coverage is 0% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 85.37%. Comparing base (8a1b04d) to head (ec50558).
⚠️ Report is 2 commits behind head on master.

Files with missing lines	Patch %	Lines
taskiq/cli/worker/run.py	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #686      +/-   ##
==========================================
- Coverage   85.37%   85.37%   -0.01%     
==========================================
  Files          68       68              
  Lines        2660     2659       -1     
==========================================
- Hits         2271     2270       -1     
  Misses        389      389              

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