Normalize English dictated date phrases

[SeoFood]

Context

This is the focused follow-up split out of #599 after the broader spoken-number normalization work was narrowed and partially completed.

Already handled elsewhere:

• Cardinal number words: Add generic transcription number normalization #647 / Add multilingual number word normalization #648
• English ordinals: Add English ordinal number normalization #655
• English digit sequences: Add English digit-sequence number normalization #693

The remaining user-visible gap from #599 is date/date-like dictation, especially phrases such as July twenty eighth.

Scope

Add a conservative date-aware ITN layer for English dictated dates, using recognized month context to avoid broad ordinal false positives.

Examples to cover:

• July twenty eighth -> July 28
• May twenty third -> May 23
• June first -> June 1
• January two -> January 2

The implementation should ride the existing transcriptionNumberNormalizationEnabled normalization path and should be safe to apply after the current cardinal, ordinal, and digit-sequence handling.

Non-goals for this issue

• Numeric date-format conversion such as 07/28/2026
• Locale-specific date ordering
• Relative dates such as next Tuesday
• Phone numbers, currency, measurements, or arbitrary prompt-driven formatting
• Broad bare ordinal conversion outside recognized date context

Acceptance criteria

• Month + spoken day phrases normalize to a compact date form without requiring a workflow or prompt.
• Existing cardinal, ordinal, decimal, and digit-sequence normalization behavior does not regress.
• Tests cover recognized month names, month abbreviations if supported, bare ordinal false-positive avoidance, and idempotency for already formatted dates.

Refs #599