Reuse pre-built args HashSet in handle_tokenize

[jserv]

This passes existing HashSet<&str> from main() instead of rebuilding it from the raw args slice. Move the HashSet import to module scope.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 68.40%. Comparing base (511ea60) to head (2f77d04).
⚠️ Report is 2 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main      #15   +/-   ##
=======================================
  Coverage   68.40%   68.40%           
=======================================
  Files          11       11           
  Lines         769      769           
=======================================
  Hits          526      526           
  Misses        243      243           

Flag	Coverage Δ
unittests	68.40% <ø> (ø)

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