docs: mark 1.0 — first stable release

Promote the 0.10 changelog entry to 1.0; feature-complete across web and
Android. Android versionName was already 1.0.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

CHANGELOG.md

@@ -53,7 +53,9 @@ Versioning: two-part `MAJOR.MINOR` — each release bumps the minor (features an
 
 ---
 
-## [0.10] — 2026-06-25
+## [1.0] — 2026-06-25
+
+🎉 **First stable release.** NovaSonic is feature-complete across web (PWA) and Android: streaming, lyrics, artist pages, playlists, importer/downloads, Audiobookshelf, and — new in this release — full offline downloads on Android. Further work lands as point releases.
 
 ### Added
 - **Android** — Offline downloads: download albums and playlists to device storage with a single tap; album download button is in the album hero row (▶ / shuffle / ↓), playlist button next to the edit toggle. Tapping again resumes / re-downloads any missing songs (already-downloaded tracks are skipped)