feat(lyrics,art): real-time synced lyrics & multi-protocol terminal album art

Closes #23.

Adds two new zero-dependency engine packages and wires them into the TUI.

pkg/lyrics
- LRCLIB exact lookup, LRCLIB search fallback, then NetEase.
- LRC parser handling [mm:ss(.xx|.xxx)], multiple stamps per line and
  [offset:NNN]; ActiveIndex/Progress resolve the line for a playback offset.
- SplitTrackTitle turns dirty ICY titles into artist/title, returning nothing
  for station names and advert slugs so no pointless lookup is made.
- RAM LRU plus a disk cache under ~/.cache/halpradio/lyrics/, with negative
  caching so unmatched stations do not hammer the providers.

pkg/art
- Cover lookup from iTunes, Deezer, MusicBrainz/Cover Art Archive and
  optionally Last.fm, capped and validated before use.
- Terminal renderers for the Kitty graphics protocol, iTerm2 inline images,
  Sixel, truecolor half-blocks and Braille, plus env-based auto-detection.
- Every renderer returns exactly `rows` lines whose lipgloss.Width equals
  `cols`, so escape-sequence transports cannot shift the Bubble Tea layout.

TUI integration
- L opens a lyrics drawer that takes its own columns rather than overlapping
  the station list, auto-scrolling around the active line with a progress
  gauge; j/k scroll unsynced sheets and , / . nudge the sync, which persists.
- A opens a floating cover art viewer; the drawer also carries a thumbnail
  when the terminal is tall enough to spare the rows.
- Lookups run as tea.Cmds keyed on a station+track signature, so every play
  path is covered and late results for a superseded track are dropped.
- Artwork is rasterised in the update loop on a new cover, a resize or a
  surface toggle, keeping component views pure; a closed surface emits the
  protocol's image-delete escape so Kitty placements do not linger.

While in the analog tuner, L keeps sweeping the dial. That branch also had
its step sign inverted, so a fast sweep right now raises the frequency.

No new module dependencies.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

Author: Kenth Fagerlund

AGENTS.md

@@ -43,6 +43,8 @@ halpradio/
     ├── party/            # P2P mesh synchronized radio rooms, Argon2id/AES-256-GCM E2EE & protocol engine
     ├── plugin/           # Wazero Wasm sandbox, capability permissions, host API, registry client
     ├── radio/            # Store (bundled/local/favorites), Station struct, RadioBrowser HTTP client
+    ├── lyrics/           # LRCLIB & NetEase lyric providers, LRC parser, RAM + disk cache
+    ├── art/              # Cover art providers & Kitty/iTerm2/Sixel/half-block/Braille renderers
     ├── theme/theme.go    # Theme struct & color palettes (tokyonight, catppuccin, synthwave, nord, gruvbox, dracula)
     ├── timer/            # Pomodoro focus interval engine, sleep timer with volume fade, OS event dispatcher
     ├── ui/               # Model, Update loop, View orchestrator, keymaps
@@ -69,6 +71,10 @@ halpradio/
 - **Rule**: Never hardcode hex color strings (e.g. `#7aa2f7`) inside component files.
 - Always use active theme tokens provided by `m.theme` (e.g. `theme.Primary`, `theme.Secondary`, `theme.Border`, `theme.Playing`).
 
+### 3b. Terminal Image Rendering (`pkg/art`)
+- Every renderer must return exactly `rows` lines whose `lipgloss.Width` equals `cols`. Escape-sequence transports (Kitty APC, iTerm2 OSC 1337, Sixel DCS) pad with spaces so Bubble Tea's layout arithmetic still holds.
+- **Rule**: Rasterise artwork in [`pkg/ui/update.go`](./pkg/ui/update.go) (on a new cover or a `tea.WindowSizeMsg`), never inside a component `View()`.
+
 ### 4. Error Handling & TUI Resilience
 - Audio stream errors or invalid URLs should update `player.Manager` status to `StatusError` or populate `lastError`.
 - **Rule**: Never call `panic()` or `os.Exit()` inside UI updates or stream handlers. The TUI must remain interactive even when a stream fails.

CLAUDE.md

@@ -16,11 +16,14 @@
 - `pkg/player/player.go`: Multi-backend player manager (`mpv`, `vlc`, `ffplay`, etc.) + native Go fallback (`oto/v3` + `go-mp3`) and ICY stream metadata listener.
 - `pkg/radio/store.go`: Station catalog store (`bundled`, `local`, `favorites`), YAML/JSON persistence.
 - `pkg/radio/radiobrowser.go`: RadioBrowser HTTP search client.
+- `pkg/lyrics/`: LRCLIB + NetEase lyric providers, LRC timestamp parser, RAM/disk cache.
+- `pkg/art/`: cover art providers and terminal image renderers (Kitty, iTerm2, Sixel, half-block, Braille).
 - `pkg/theme/theme.go`: Theme definitions (`tokyonight`, `catppuccin`, `synthwave`, `nord`, `gruvbox`, `dracula`).
 - `pkg/timer/`: Pomodoro focus state machine, sleep timer countdown, and OS notification dispatcher.
 - `pkg/ui/model.go` & `update.go` & `view.go`: Bubble Tea Model, Update loop, View orchestrator.
-- `pkg/ui/components/`: Sub-views (`header`, `sidebar`, `stationlist`, `playerbar`, `statusbar`, `visualizer`, `modals`, `whichkey`).
-- `pkg/util/`: Path resolution (`~/.config/halpradio/`) and clipboard helper.
+- `pkg/ui/components/`: Sub-views (`header`, `sidebar`, `stationlist`, `playerbar`, `statusbar`, `visualizer`, `modals`, `whichkey`, `lyrics`, `art`).
+- `pkg/ui/nowplaying.go`: Lyric/artwork lookup commands, sync offset, and the artwork rasterisation step.
+- `pkg/util/`: Path resolution (`~/.config/halpradio/`, `~/.cache/halpradio/`) and clipboard helper.
 
 ## 🎨 Code Style & Architectural Constraints
 1. **Thread Safety**: Always protect shared state in `player.Manager` with `m.mu.Lock()` / `m.mu.Unlock()`.
@@ -29,3 +32,4 @@
 4. **Theme Tokens**: Never hardcode hex color strings in UI components. Use `theme.Primary`, `theme.Border`, `theme.Playing`, etc.
 5. **Resilience**: Never call `panic()` or `os.Exit()` on playback errors. Set `m.status = StatusError` and let the TUI inform the user gracefully.
 6. **Verification**: Always run `go test ./...` and `gofmt -s -w .` after making modifications.
+7. **Terminal Images**: Every `art.Renderer` protocol must return exactly `rows` lines whose `lipgloss.Width` equals `cols`, so escape-sequence transports cannot shift the surrounding layout. Rasterise artwork in `pkg/ui/update.go`, never inside a component `View()`.

README.md

@@ -322,6 +322,65 @@ Internet radio ICY streams often emit dirty titles like:
 
 ---
 
+## 📜 Real-Time Synced Karaoke Lyrics & Multi-Protocol Terminal Album Art
+
+Modern terminals grew real graphics capabilities, so `halpradio` uses them. Press `L` for a live lyric sheet that scrolls itself, and `A` for the cover art of whatever is on air — all without leaving the terminal.
+
+### 🎤 Live Synced Lyrics Drawer (`L` key)
+- **LRCLIB First**: Queries [LRCLIB](https://lrclib.net) with the artist, title and duration taken from ICY stream metadata or the acoustic fingerprint, then falls back to NetEase when LRCLIB has no match.
+- **Auto-Scrolling Karaoke View**: When timestamped `.lrc` data exists, the drawer highlights the line being sung, fades the surrounding lines, and draws a progress gauge across the active line.
+- **Manual Scroll For Plain Text**: Unsynced lyrics render as a formatted sheet you scroll with `j` / `k`.
+- **Sync Nudge**: Internet radio exposes no seek position, so the lyric clock starts when the station announces a new title. Press `,` and `.` to shift the sync in 0.5 second steps when a station announces late or early.
+- **Never Blocks The UI**: Every lookup runs as a Bubble Tea command off the update loop, so the TUI stays responsive on slow connections, and the drawer takes its own columns rather than overlapping the station list.
+- **Disk & Memory Cache**: Sheets are memoised in RAM and cached under `~/.cache/halpradio/lyrics/`, and stations with no match are negative-cached so the APIs are not hammered every track.
+
+### 🖼️ Multi-Protocol Album Art (`A` key)
+`halpradio` detects your terminal's best image transport at startup and encodes artwork for it:
+
+| Priority | Protocol | Terminals |
+|---|---|---|
+| 1 | **Kitty Graphics** | Ghostty, Kitty, WezTerm |
+| 2 | **iTerm2 Inline Images** | iTerm2, WezTerm |
+| 3 | **Sixel** | Foot, xterm, mlterm, yaft |
+| 4 | **Truecolor Half-Block** | every 24-bit colour terminal |
+| 5 | **Braille** | 256-colour and monochrome fallback |
+
+- **High-Res Cover Lookup**: Artwork is resolved from the iTunes Search API, Deezer, MusicBrainz plus the [Cover Art Archive](https://coverartarchive.org/), and Last.fm when you supply `lastfm_api_key`.
+- **No Distortion On Basic Terminals**: The half-block and Braille renderers letterbox the image to keep covers square, and every renderer emits output padded to an exact cell grid so the surrounding layout never shifts.
+- **Two Surfaces**: A thumbnail sits at the top of the lyrics drawer, and `A` opens a floating full-size viewer showing the album, the provider and the active protocol.
+- **Cached Locally**: Downloaded covers live under `~/.cache/halpradio/art/`.
+
+```text
+┌─ 📻 CATALOG ──────────────────┬─ 📜 LIVE LYRICS ───────────────┐
+│  ▶ SomaFM Groove Salad        │      ▄▄▄▄▄▄▄▄▄▄▄▄              │
+│    Nightwave Plaza            │      █ ALBUM ART █             │
+│    Radio Paradise             │      ▀▀▀▀▀▀▀▀▀▀▀▀              │
+│    KEXP 90.3                  │       🖼 iTunes                 │
+│                               │  Tycho - A Walk                │
+│                               │                                │
+│                               │    I've been wandering         │
+│                               │  ► Searching for a signal ◄    │
+│                               │    Everything is quiet         │
+│                               │  ━━━━━━━━━━━───────            │
+│                               │  ⏱ Synced via LRCLIB           │
+│                               │  L close · , . sync            │
+└───────────────────────────────┴────────────────────────────────┘
+```
+
+Tune the feature from `~/.config/halpradio/config.yaml`:
+```yaml
+lyrics_enabled: true          # LRCLIB / NetEase synced lyrics engine
+lyrics_auto_open: false       # open the drawer on startup
+lyrics_offset_ms: 0           # persistent sync correction
+album_art_enabled: true       # terminal cover art renderer
+album_art_protocol: auto      # auto | kitty | iterm2 | sixel | halfblock | braille | off
+lastfm_api_key: ""            # optional extra cover art provider
+```
+
+Set `HALPRADIO_NO_ART=1` to disable image rendering for a single run, or `HALPRADIO_ART_PROTOCOL=halfblock` to force a transport when detection guesses wrong.
+
+---
+
 ## 🎉 Terminal Party Line: P2P Mesh Synchronized Radio Rooms & Reactions
 
 Share the groove with teammates, study groups, or friends with zero central audio relaying! `halpradio` features an end-to-end encrypted (E2EE) P2P mesh party system powered by WebRTC data channels:
@@ -378,6 +437,9 @@ Press `?` or `F1` anywhere in **halpradio** to open the floating **WhichKey Over
 | **Discovery & Sharing** | `Ctrl+p` | Open **Party Room Manager** (P2P mesh synchronized listening & room setup) |
 | | `1` - `5` | Send live floating ASCII reaction (🔥 ❤️ ☕ 🚀 👀) when in Party Room |
 | | `I` | **Identify playing track** via acoustic stream fingerprinting (Chromaprint / AcoustID) |
+| | `L` | Toggle **live synced lyrics drawer** (LRCLIB / NetEase) |
+| | `A` | Toggle **album art viewer** (Kitty / Sixel / iTerm2 / half-block) |
+| | `,` / `.` | Nudge lyric sync backward / forward by 0.5s (lyrics drawer open) |
 | | `y` | Yank / copy track metadata (`Artist - Title`) or identified song to system clipboard |
 | | `o` | Open streaming search in default web browser (Spotify, YT Music, Apple, DDG, Google) |
 | | `s` | Star / bookmark track to `~/.config/halpradio/saved_tracks.txt` (on History tab) |
@@ -510,6 +572,7 @@ Explore detailed technical documentation in the [`docs/`](./docs) folder:
 - 🔌 **[Plugin & Extension System Guide](./docs/PLUGINS.md)**: Sandboxed WebAssembly (Wasm) architecture, capability permissions, developer SDK, and publishing to the official registry.
 - 🎵 **[Audio Engine & Stream Player](./docs/AUDIO_PLAYER.md)**: Multi-backend auto-detection (`mpv`, `vlc`, `ffplay`, native Go), process lifecycle, and real-time ICY metadata extraction.
 - 📻 **[Station Catalog & RadioBrowser Integration](./docs/STATION_MANAGEMENT.md)**: Station storage hierarchy (`stations.yaml`, local config, favorites), RadioBrowser API client, and PR export workflow.
+- 📜 **[Synced Lyrics & Terminal Album Art](./docs/LYRICS_AND_ART.md)**: LRCLIB / NetEase lyric providers, LRC parsing, playback-position estimation, cover art providers, and the Kitty / iTerm2 / Sixel / half-block / Braille renderers.
 - 🎨 **[Theme System & Audio Visualizers](./docs/THEME_SYSTEM.md)**: Lipgloss styling system, theme palettes, and TUI visualizer algorithms.
 - ⚙️ **[Configuration & Keybindings](./docs/CONFIGURATION.md)**: Directory layout, `config.yaml` options, CLI flags, and complete keymap reference.
 - 📦 **[Packaging & Distribution Guide](./docs/PACKAGING.md)**: Specifications for Homebrew, Arch Linux AUR, Docker, Scoop, and Nix.

docs/ARCHITECTURE.md

@@ -53,6 +53,8 @@ halpradio/
 ├── docs/                 # Detailed technical documentation
 └── pkg/
     ├── app/              # CLI flag parsing, configuration loading & app bootstrap
+    ├── art/              # Cover art providers plus Kitty / iTerm2 / Sixel / half-block / Braille renderers
+    ├── lyrics/           # LRCLIB & NetEase lyric providers, LRC parser, RAM and disk caches
     ├── player/           # Multi-backend audio playback engine & ICY stream reader
     │   └── fingerprint/  # Acoustic stream recognition, Chromaprint / AcoustID client, LRU cache
     ├── party/            # P2P mesh synchronized radio rooms, Argon2id/AES-256-GCM E2EE & protocol engine
@@ -61,7 +63,7 @@ halpradio/
     ├── theme/            # Theme definitions & color palette registry
     ├── timer/            # Pomodoro focus engine, sleep timer with volume fade, and OS event dispatcher
     ├── ui/               # Main Bubble Tea Model, Update, View, and Keymap logic
-    │   └── components/   # Modular UI sub-views (Header, StationList, PlayerBar, Visualizer, Modals, PartyBar)
+    │   └── components/   # Modular UI sub-views (Header, StationList, PlayerBar, Visualizer, Modals, PartyBar, LyricsDrawer, AlbumArt)
     └── util/             # OS configuration directory resolution & clipboard utilities
 ```
 
@@ -71,6 +73,8 @@ halpradio/
 |---|---|---|
 | [`pkg/app`](../pkg/app/app.go) | `Run()`, `RunPluginCLI()` | Parses CLI flags (`--backend`, `--theme`, `--version`, `--fingerprint`, `--auto-identify`), handles CLI subcommands (`remote`, `plugin`, `party`), sets up store, instantiates `player.Manager`, initializes `tea.Program`. |
 | [`pkg/party`](../pkg/party/sync.go) | `Session`, `MeshNode`, `Packet`, `Crypto` | P2P mesh synchronized radio rooms, WebRTC data channels, Argon2id key derivation & AES-256-GCM encryption, sub-second playback sync, host election, ASCII reaction bus. |
+| [`pkg/art`](../pkg/art/client.go) | `Client`, `Cover`, `Renderer`, `Protocol` | Resolves high-resolution cover art from iTunes, Deezer, MusicBrainz / Cover Art Archive and Last.fm, then encodes it for the terminal's best image transport with RAM and disk caching. |
+| [`pkg/lyrics`](../pkg/lyrics/lrclib.go) | `Client`, `Sheet`, `Line`, `ParseLRC()` | Queries LRCLIB and falls back to NetEase, parses `.lrc` timestamps, resolves the active line for a playback offset, and caches sheets in RAM and on disk. |
 | [`pkg/player`](../pkg/player/player.go) | `Player`, `Manager`, `TrackInfo` | Detects audio CLI backends (`mpv`, `vlc`, `ffplay`, etc.) or falls back to native Go audio. Runs ICY metadata streaming goroutine. |
 | [`pkg/player/fingerprint`](../pkg/player/fingerprint/client.go) | `Client`, `Result`, `LRUCache` | Captures 5s audio buffers, computes Chromaprint subfingerprints, queries AcoustID & MusicBrainz APIs with LRU caching. |
 | [`pkg/plugin`](../pkg/plugin/manager.go) | `Manager`, `Sandbox`, `Manifest`, `RegistryClient` | Executes sandboxed WebAssembly plugins via Wazero with capability checks (`network`, `storage`, `events`). Fetches and verifies official registry packages. |

docs/CONFIGURATION.md

@@ -70,6 +70,14 @@ fingerprint_enabled: true   # Enable on-demand acoustic recognition via 'I' (Chr
 auto_identify: false        # Automatically identify music when streams lack ICY track metadata
 acoustid_api_key: ""        # AcoustID API key (leave empty to use default halpradio client key)
 
+# Synced Lyrics & Terminal Album Art
+lyrics_enabled: true        # Enable the LRCLIB / NetEase synced lyrics drawer ('L' key)
+lyrics_auto_open: false     # Open the lyrics drawer automatically on startup
+lyrics_offset_ms: 0         # Persistent lyric sync correction in milliseconds (',' / '.' adjust live)
+album_art_enabled: true     # Enable terminal cover art rendering ('A' key)
+album_art_protocol: auto    # auto | kitty | iterm2 | sixel | halfblock | braille | off
+lastfm_api_key: ""          # Optional extra cover art provider (iTunes, Deezer & Cover Art Archive need no key)
+
 # Experimental Features (On Hold)
 experimental_tuner: false   # Enable experimental Analog Frequency Tuner on Tab 0 (see docs/TUNER.md)
 ```