feat: Dayparting PR 3/5 — on the air (ceremony, flavor line, show idents, spectator)

[genwave-radio]

📛 Dayparting epic — PR 3 of 5 (stacked on #456 · PLAN T248–T252)

The audible slice — shows reach the ear and the public face:

• 🎙️ Show-aware ceremony (T248): sign-on carries the incoming show's name + flavor; sign-off may name both shows; same-persona different-show = ONE transition piece (the F92.4 incoming-welcome rung as designed behavior); F92.3 dedupe = persona AND show; the arm-once key widened to show ids (closes a latent show-only-edit swallow); showless ceremony prompts byte-identical to the Story243 goldens.
• 🗣️ The flavor line (T249): shares F107.5's single extra-line slot — context wins, the show gate stays open ("never even ask" semantics so a lost slot never burns cadence); ShowFlavorLineGate per-show cadence (Station:Shows:PatterCadenceMinutes, Live, default 0 — the demo opts in); flavor rides unfenced (owner-config, the Soul precedent) with the T254 imported-flavor constraint recorded at the injection site; preview never consults the seam (pinned).
• 📻 Show idents (T250): one-query scoped-first pool (F95.4 inherited structurally; scoped rows never air outside their show); templated show-line floor ("You're listening to {show} on {station}." — zero LLM, forever-cached, rename re-keys by construction); ladder RATIFIED (Dean 2026-08-10): authored beats template — F117.2 amended in SPEC; estimator Exact memo re-keyed (voice, show) so mixed-show durations never corrupt boundary-fit; IMediaCatalog/IPatterDurationEstimator evolved via genuinely-additive DIM overloads (3-arg members byte-identical — no published-contract break).
• 🌐 Spectator (T251): now-playing show {name, tagline} | null + upNext.show (name-only by type shape); the same-persona collapse widened to persona AND show (the demo's single-DJ seed makes every flip that shape); flavor absent structurally AND value-level (distinct-string fixtures asserted absent from raw payloads); the dj-vs-show boundary-skew caveat documented (gh-spectator: DJ attribution lags a schedule change while queued patters drain #259 lineage).
• 🔌 T252 wire (orchestrator-run, engine-less local stack): PG→repository→resolver show identity live; spectator serves with honest standby; zero flavor bytes across all five public routes (grep-proven). The on-air behaviors were proven through the real production chain in specs (60-pull simulated drains through the real Orchestrator/resolver).

✅ Gates

Every task opus-review-gated (T248 ×2, T249 ×2, T250 ×2, T251 ×2 — catches included a boundary-fit estimator corruption, a published-DIM binary break, an upNext erasure at ruled-real boundaries, and a renderer whitespace bug found by a review-demanded fact). Suites: non-Integration 0 failed (Host 1554, Tts 474, Orchestration 267, Architecture 95/95), MediaLibrary Integration 671/0, -warnaserror 0/0, SEAMS green.

🖐️ Live checklist for the pinned deploy (the T229/T233 pattern)

• A same-DJ show flip airs exactly ONE transition piece naming the incoming show (booth: one SignOn row, no SignOff)
• With Station:Shows:PatterCadenceMinutes > 0: a flavor-colored line appears in a break within the cadence; never two extra lines in one break (weather on = context wins)
• Top-of-hour during a show with no scoped idents: an authored station ident airs (show-stamped row); with the pool empty: "You're listening to ⟨show⟩ on ⟨station⟩."
• Spectator card shows show name+tagline while airing, upNext.show before a flip — including the same-DJ flip
• 👁️ The documented dj-vs-show boundary skew (outgoing DJ beside incoming show during a straddle's crossing track) — eye-check it reads acceptably (gh-spectator: DJ attribution lags a schedule change while queued patters drain #259 lineage; a full track window, not a flicker)
• Showless station: byte-identical sound and payloads (no shows configured = nothing changes)