️🛠 - Mobile release detail view and preview playback

[maxwellmattryan]

Description

Full release detail screen with track list and integrated audio preview player, including background playback support.

Prerequisites: #79 (iOS audio session) and #80 (proxy validation spike) must be complete before building playback features to ensure the audio proxy works on iOS.

Release detail view (navigated from feed tap):

• Large artwork at top
• Artist, title, label, release date, source URL ("Open in Browser")
• Notes field — editable (inline editing with auto-save on blur)
• Tags display — assignable (tap to open tag picker, changes apply immediately)
• Track list with position, name, duration, play button

Preview playback:

• Tap track → resolve stream URL (reuse fetch_preview_stream command)
• Stream caching: Audio bytes are cached locally in discovery_stream_cache (same as desktop). On playback, always check local cache first — only fetch from external URL if no cached data exists or the cache entry has expired. This enables full offline/airplane mode playback of previously listened tracks.
• Mini-player bar appears at the bottom of the main view (above safe area): artwork, track name, play/pause, progress
• Mini-player persists across drawer open/close and navigation
• Swipe up mini-player → expanded player: large artwork, scrubber, prev/next track
• Reuse previewPlayer.ts service (HTML5 Audio in WebView) from $shared/services/
• Reuse playerStore preview playback state from $shared/stores/

Background playback:

• Audio continues when app is backgrounded or screen is lock (enabled by ️🛠 - iOS audio session and background playback #79)
• Lock screen shows Now Playing controls with track info and artwork
• Previous/next track navigation works from lock screen

Stream proxy: Reuse proxy.rs on mobile (axum runs in Tauri mobile — validated by #80)

Key files:

• apps/mobile/src/lib/components/discovery/ReleaseDetail.svelte — new
• apps/mobile/src/lib/components/player/MiniPlayer.svelte — new
• apps/mobile/src/lib/components/player/ExpandedPlayer.svelte — new
• shared/services/previewPlayer.ts — reuse
• shared/stores/player.ts — reuse

Dependencies: #53 (discovery feed), #79 (iOS audio session), #80 (proxy validation spike)

Open questions

• Should the expanded player use a swipe-up gesture or a tap-to-expand pattern?
• Should the mini-player show a progress bar or just the current track info?
• How should the tag picker modal look on mobile? Full-screen bottom sheet with category sections?

Acceptance criteria

• Release detail displays all metadata and track list
• Notes are editable inline with auto-save
• Tags are assignable via a tag picker modal
• Tapping a track starts preview playback
• Cached streams are served from local DB without network requests
• Streams are only fetched externally when no valid cache entry exists
• Previously played tracks are playable in airplane mode
• Mini-player shows during playback, persists across navigation
• Expanded player accessible via swipe-up or tap
• Previous/next track navigation within release
• Audio continues playing when app is backgrounded
• Lock screen shows Now Playing info with playback controls
• Stream resolution and proxy caching work on iOS

Tasks

TBD