docs: the voyage app in DESIGN, PRODUCT, AGENTS, ARCHITECTURE, DECISIONS, TODO

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docs/DECISIONS.md

@@ -90,3 +90,18 @@ Roman names (Ulysses, Minerva, Jove); EPIC uses the Greek ones. Both are public
 **Decision:** the album data has no Odysseus character theme. **Why:** character themes are derived from
 singers, and Odysseus sings in 35 of 40 songs, so his thread marked almost every stop and crowded the
 timeline ("+28 more"). His story is carried by the musical motifs (Warrior of the Mind, Just a Man, …).
+
+## 2026-10-30 — The voyage app (spec 002): structure and v1 choices
+
+- **Album data is separate from the mockups' data** (`src/data/album/` vs `src/data/types.ts`/`sample.ts`),
+  so the 17 mockups keep working unchanged.
+- **App at `/`, gallery at `/mockups/`.** The mockups stay served as the design record.
+- **Odyssey references are a book plus keywords**, not line numbers: the public-domain prose translations
+  have no line numbers. Links point at Butcher & Lang (Gutenberg #1728).
+- **Landings:** cave = Polyphemus, Survive; arena = God Games; hall = all five Ithaca songs.
+- **Transitions:** same saga sails, the adjacent saga drops its frieze, further jumps fade. Last request
+  wins; a curtain left down by a cancelled step is lifted by the next one.
+- **Play voyage is silent** (3.4s per song): starting audio without a click is close to autoplay.
+- **Fan works are empty in v1** with an empty state; no invented works are shown.
+- **Without WebGL** the frieze is the stage (dropped, never lifted), so the album stays browsable.
+- **Back to sea** leaves a landing but keeps the song.