Add French (fr-fr) language support

[toto-polo]

Add French (fr-fr) language support

This PR adds complete French language support following the same structure
as the existing Italian (it-it) implementation.

Tools used

Claude Code Pro for implementation
Google Gemini in Android Studio to verify code compilation

Files added

Resources (config/fr-fr/):

• tokenizer.json — Tokenizer with all French number words (0–99 including
  the irregular 70–79 and 80–99 forms), ordinals, months, weekdays, duration
  words, and date/time tokens
• date_time.json — Date/time formatting with French-specific decade_format
  rules covering soixante-dix (70), quatre-vingts (80), etc.
• date_time_test.json — Year/date/date-time formatting tests
• *.word files — Translations for duration unit words (seconde, minute,
  heure, jour and plurals)

Source (lang/fr/):

• FrenchFormatter.kt — Number pronouncer implementing French-specific
  subHundred logic (soixante-dix, quatre-vingts) and ordinal suffixes (-ième,
  with special cases for cinq→cinquième, neuf→neuvième, etc.)
• FrenchNumberExtractor.kt — Number parser with custom numberLessThan1000Fr
  handling space-separated forms like "soixante dix-sept" (70–79) and
  "quatre vingt" (80+)
• FrenchDateTimeExtractor.kt — Date/time parser including "moins le quart"
  (quarter to) support via special_minute_before
• FrenchParser.kt — Top-level parser wiring the above components

Modified:

• ParserFormatterBuilder.kt — Registered "fr" locale

Key implementation notes

• French 70–79: "soixante" (60) + a teen (10–19). Both hyphenated tokens
  (e.g. soixante-dix-sept) and space-separated forms are handled.
• French 80–99: "quatre" (4) × "vingt" (20) ± remainder. The tokenizer
  provides pre-built hyphenated forms; the extractor handles the
  space-separated case.
• Ordinals: strip trailing "s" (quatre-vingts → quatre-vingtième), then
  apply -ième with phonetic adjustments (cinq+u, neuf→v, drop final e).
• Duration formatting uses "un" regardless of grammatical gender (same
  approach as Italian).