feat(tts): phone numbers as digits + the flatten keeps the pause (gh-#700, gh-#703)

[genwave-radio]

🎯 What

PR-2 of the launch-polish epic: STORY-464 (phone numbers are spoken as digits) + STORY-465 (the flatten keeps the pause). Built on PR-1 (#830, merged); four commits ahead of main.

Fixes #700, fixes #703.

• T544 — phone shape lives in Core (gh-TTS: phone numbers air as arithmetic — "555-0142" is spoken as "five hundred and fifty five … one hundred and forty two" #700). GenWave.Core.PhoneShape owns the four NANP shapes; PhoneShapeCheck in Ads references it and keeps no \d{3} regex of its own (fitness law in Architecture.Tests).
• T545 — phone numbers are spoken as digits (gh-TTS: phone numbers air as arithmetic — "555-0142" is spoken as "five hundred and fifty five … one hundred and forty two" #700). SpeechText.FlattenSegment splits each segment around phone matches and speaks them digit by digit, groups joined with ", ". Years, times (7:30) and plain counts are untouched.
• T546 — the flatten keeps the pause (gh-TTS: the speakability flatten strips commas, colons and dashes so lines run on — and stitched ad lines get random 0.25–1.1 s gaps #703). Commas survive the flatten; a loose colon, dash or ellipsis becomes a comma; runs collapse to one; in-word hyphens and ac/dc stay (F68 law). MergePolicyVersion moves to f97.4+gh541+gh703 (F198.2) so every cached evergreen line re-renders once.
• T547 — same-speaker lines follow without a hesitation (gh-TTS: the speakability flatten strips commas, colons and dashes so lines run on — and stitched ad lines get random 0.25–1.1 s gaps #703). CrosstalkTimeline clamps a same-speaker transition into [0.20, 0.35] s from the same seeded draw; cross-speaker transitions keep [0.2, 0.8] s. Both assembler paths (crosstalk speaker enum, cast tag) thread the flags through MixAsync.

🔬 Wire evidence (T548, dev station on the branch image)

STORY-464 AC3/AC4/AC6–AC8 and STORY-465 AC1–AC6 through POST /api/tts/normalize-preview on the deployed api (the one SpeechText.Normalize chokepoint every voice uses):

Input	Spoken
Call 555-0142 today	call five five five, zero one four two today
Call (812) 555-0199 now	call eight one two, five five five, zero one nine nine now
Back in 1994 and 2026	back in 1994 and 2026
at 7:30 tonight	at 7:30 tonight
over 1000 tracks	over 1000 tracks
Tonight, on GenWave, the hits	tonight, on genwave, the hits
Coming up: the news	coming up, the news
Rock — and roll – tonight - late	rock, and roll, tonight, late
Wait for it… now	wait for it, now
Well, — well	well, well
re-render the drive-time show	re-render the drive-time show
AC/DC and Ke$ha play... now	ac/dc and ke$ha play, now
Call us: 555-0142	call us, five five five, zero one four two
Coming up, [pause:1s] the news	coming up, [pause:1s] the news

STORY-464 AC5 (every voice) — the same three-line spot rendered through POST /api/ads + /preview on the t545 image and again on the t547 image; the text Kokoro logged as its input:

t545: wire diner the late-night stop on route nine breakfast all night coffee always hot.
      call eight one two, five five five, zero one four two for a table or just walk in.
t547: wire diner, the late-night stop on route nine, breakfast all night, coffee, always hot.
      call eight one two, five five five, zero one four two for a table, or just walk in.

STORY-465 AC8/AC9 — a four-line spot (ANNOUNCER ×3, VOICE1) previewed with the same seed before and after T547: gaps 0.729 / 0.737 / 0.451 s → 0.332 / 0.334 / 0.451 s; the preview wav shrank 0.799 s against a predicted 0.799 s.

F198.2 re-render — after each api restart on the new MergePolicyVersion the booth log shows the evergreen lines re-rendering (five patter-aired rows in the first 40 s, AIR rows resuming within twenty minutes: first LeadIn at 20:30:57Z after the 20:12Z restart, 30 renders ahead of it).

STORY-465 AC10 (manual) — clip pairs for Dean's ear at ~/pace-ear-check/2026-09-22-flatten-pause/index.html (pause pair t545→t547, gap pair t546→t547, same script each).

Full solution (dotnet test GenWave.sln --filter "Category!=Integration", Host with MaxParallelThreads=3): 0 failed across all 9 projects (Host 3082 passed / 48 skipped, Tts 907 / 16 skipped). admin-ui untouched.

⚠️ Follow-ups (not fixed here)

1. No spec runs AssembleCastAsync end to end with two consecutive same-tag lines; AC8 pins CrosstalkTimeline and the wire proof covers the assembler. A one-fact wiring spec would close that gap.
2. Comma/ender adjacency (well,.) is deliberately not normalised; only a true trailing , collapses.
3. STORY-464 AC2 lives in Architecture.Tests rather than Core.Tests: referencing Ads from Core.Tests makes the GenWave.Loudness namespace shadow the Loudness record there (CS0118). Noted in both spec headers.