fix(llm): guard the embellishment license and quirk examples (gh-#188)

[genwave-radio]

Closes #188.

🔧 What changed

• 🛡️ System scaffold: "You may embellish with genuine knowledge of the track, artist, or era" → guarded license: era/genre color welcome, but never state specific facts about the artist or track you were not given, never alter the artist's name or the track's title, when unsure stay with what the prompt provides. This is the line that let a 7B-class model rename LaBarcaDeSua to "Barcarola" on air and invent "rural Cuba" / "Brooklyn's indie scene" origins.
• 🎭 Quirk example guidance: a constant line now rides directly under the Quirks: line — examples illustrate style; invent fresh specifics each break; never reuse an example's literal values on air. Emitted only when quirks are shown, so a quirk-less persona prompt stays byte-identical to its previous shape. This targets The Archivist airing the literal "item four-seven-one-two" break after break while still leaving her catalog-number bit fully intact.

🧪 Specs

Issue188_PromptGuardrails: guarded license present, old license absent, guidance sits immediately beneath Quirks, quirk-less prompt unchanged.

✅ Verification

• Build: 0 warnings / 0 errors
• Tts 227 (4 new), Host 1,082, Orchestration 154 — all green
• Persona quirks themselves untouched — The Archivist keeps her accession numbers, she just has to invent them now, per her own job description

🤖 Generated with Claude Code