Add Lyrics practice: search, translate, and read Spanish song lyrics

New feature in the Practice tab that lets users search for Spanish songs
by artist + title, fetch lyrics from LRCLIB (free, no API key), pull
album art from iTunes Search API, auto-translate to English via Apple's
on-device Translation framework, and save for offline reading.

Components:
- SavedSong SwiftData model (local container, no CloudKit sync)
- LyricsSearchService actor (LRCLIB + iTunes Search, concurrent)
- LyricsSearchView (artist/song fields, result list with album art)
- LyricsConfirmationView (lyrics preview, auto-translation, save)
- LyricsLibraryView (saved songs list, swipe to delete)
- LyricsReaderView (Spanish lines with English subtitles)
- Practice tab integration (Lyrics button with NavigationLink)
- localStoreResetVersion bumped to 3 for schema migration

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Conjuga/SharedModels/Sources/SharedModels/SavedSong.swift

@@ -0,0 +1,25 @@
+import SwiftData
+import Foundation
+
+@Model
+public final class SavedSong {
+    public var id: String = ""
+    public var title: String = ""
+    public var artist: String = ""
+    public var lyricsES: String = ""
+    public var lyricsEN: String = ""
+    public var albumArtURL: String = ""
+    public var appleMusicURL: String = ""
+    public var savedDate: Date = Date()
+
+    public init(title: String, artist: String, lyricsES: String, lyricsEN: String, albumArtURL: String = "", appleMusicURL: String = "") {
+        self.id = UUID().uuidString
+        self.title = title
+        self.artist = artist
+        self.lyricsES = lyricsES
+        self.lyricsEN = lyricsEN
+        self.albumArtURL = albumArtURL
+        self.appleMusicURL = appleMusicURL
+        self.savedDate = Date()
+    }
+}