Tighten project documentation

[galjos]

Summary

• replace repetitive README prose with concise reference tables
• retain input constraints, multi-file behavior, and interface controls
• align package metadata and command help with the README

Tests

• 204 tests with 100% coverage
• 9 GUI/TUI end-to-end tests

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 100.00%. Comparing base (734612a) to head (2f9f9ce).

Additional details and impacted files

@@            Coverage Diff            @@
##              main       #91   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files           11        11           
  Lines          502       502           
=========================================
  Hits           502       502           

Flag	Coverage Δ
unittests	100.00% <ø> (ø)

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