chore: release 1.5.6 and improve release workflow

[Arakiss]

Summary

• allow running release.py on arbitrary branches and skip pushing
• document the automated release process
• bump version to 1.5.6 and update changelog

Testing

• ruff release.py
• OPENAI_API_KEY=dummy pytest (fails: Coverage failure: total of 30 is less than fail-under=68)

---

https://chatgpt.com/codex/tasks/task_e_68a703e864f8832abac9d5de72fdd720

[codecov-commenter]

⚠️ Please install the to ensure uploads and comments are reliably processed by Codecov.

Codecov Report

❌ Patch coverage is 90.74074% with 5 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
commitloom/services/ai_service.py	88.09%	2 Missing and 3 partials ⚠️

❌ Your project status has failed because the head coverage (68.92%) is below the target coverage (80.00%). You can increase the head coverage or adjust the target coverage.
❗ Your organization needs to install the Codecov GitHub app to enable full functionality.

@@            Coverage Diff             @@
##             main       #5      +/-   ##
==========================================
+ Coverage   67.76%   68.92%   +1.15%     
==========================================
  Files           8        8              
  Lines        1095     1123      +28     
  Branches      152      159       +7     
==========================================
+ Hits          742      774      +32     
+ Misses        302      299       -3     
+ Partials       51       50       -1     

Files with missing lines	Coverage Δ
commitloom/cli/cli_handler.py	65.91% <100.00%> (ø)
commitloom/core/analyzer.py	97.50% <100.00%> (+6.25%)	⬆️
commitloom/core/git.py	64.36% <100.00%> (+1.58%)	⬆️
commitloom/services/ai_service.py	87.50% <88.09%> (+1.63%)	⬆️

🚀 New features to boost your workflow:

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