v2.3: Major refactoring, Lavalink music system, Spotify support, CI/CD

- Full refactoring: max 200 lines/file, max 3 files/dir, KISS/DRY/SOLID
- Lavalink client 3.4.0 + LavaSrc plugin (Spotify, Apple Music, Deezer)
- 3-bot architecture: main (!), music (q!), radio (r!)
- Filters: bassboost, nightcore, vaporwave, equalizer
- Slash commands for music (/play, /skip, etc.)
- Persistent queue in SQLite, auto-leave timer
- Radio manager with auto-reconnect
- Custom welcome GIF greetings via nekos.life
- JDA 5.6.1, gson 2.14, hikaricp 6.3, all deps updated
- Fixed YouTube playback via ytmsearch (LavaSrc)
- CI/CD: Docker publish + release workflows
- SpotBugs: all real bugs fixed, ignoreFailures=false
- Checkstyle: Google Style (adapted), 0 violations

.github/workflows/release.yml

@@ -0,0 +1,33 @@
+name: Release
+
+on:
+  push:
+    tags: ["v*.*.*"]
+
+permissions:
+  contents: write
+
+jobs:
+  release:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/setup-java@v4
+        with:
+          java-version: "21"
+          distribution: "temurin"
+
+      - uses: gradle/actions/setup-gradle@v4
+
+      - name: Build JAR
+        run: ./gradlew jar --no-daemon
+
+      - name: Create Release
+        uses: softprops/action-gh-release@v2
+        with:
+          name: Loki Bot ${{ github.ref_name }}
+          body_path: CHANGELOG.md
+          fail_on_unmatched_text: true
+          files: |
+            build/libs/discord-bot-*.jar