Add FormatterModifier to message rendering and expand test coverage

[henriquemoody]

Integrate FormatterModifier into the validation message modifier chain, enabling StringFormatter formatters to be used as pipe modifiers in message templates (e.g., {{input|uppercase}}, {{input|mask:1-4:X}}). This requires bumping respect/string-formatter to ^1.7.

Add feature tests for both the Formatted validator (uppercase, lowercase, trim, number, date, creditCard, secureCreditCard, chained formatters) and the FormatterModifier in templates (all major formatters, custom parameters, multi-argument modifiers, and chained modifiers).

Assisted-by: Claude Code (Claude Opus 4.6)

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 99.47%. Comparing base (eedce8f) to head (305a7d1).
⚠️ Report is 1 commits behind head on 3.0.

Additional details and impacted files

@@            Coverage Diff            @@
##                3.0    #1690   +/-   ##
=========================================
  Coverage     99.47%   99.47%           
  Complexity      979      979           
=========================================
  Files           193      193           
  Lines          2294     2294           
=========================================
  Hits           2282     2282           
  Misses           12       12           

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