prod: UI Optimisée mise en production

- Documentation archivée et réorganisée
- Backend: Ajout tests, migrations, library service, rate limiting
- Frontend: Suppression Flutter, focus sur interface web HTML/JS
- Tailwind CSS ajouté pour le style
- Améliorations UX et corrections bugs

Generated with [Claude Code](https://claude.com/claude-code)
via [Happy](https://happy.engineering)

Co-Authored-By: Claude <noreply@anthropic.com>
Co-Authored-By: Happy <yesreply@happy.engineering>

backend/app/models/liked_track.py

@@ -0,0 +1,90 @@
+"""Liked Track model."""
+import uuid
+from datetime import datetime
+from typing import TYPE_CHECKING
+
+from sqlalchemy import String, ForeignKey, Index
+from sqlalchemy.dialects.postgresql import UUID
+from sqlalchemy.orm import Mapped, mapped_column, relationship
+
+from app.core.database import Base
+
+if TYPE_CHECKING:
+    from app.models.user import User
+    from app.models.track import Track
+
+
+class LikedTrack(Base):
+    """Liked Track model representing user's liked/favorited tracks."""
+
+    __tablename__ = "liked_tracks"
+
+    # Primary key
+    id: Mapped[uuid.UUID] = mapped_column(
+        UUID(as_uuid=True),
+        primary_key=True,
+        default=uuid.uuid4,
+        index=True,
+    )
+
+    # Foreign keys
+    user_id: Mapped[uuid.UUID] = mapped_column(
+        UUID(as_uuid=True),
+        ForeignKey("users.id", ondelete="CASCADE"),
+        nullable=False,
+        index=True,
+    )
+    track_id: Mapped[uuid.UUID] = mapped_column(
+        UUID(as_uuid=True),
+        ForeignKey("tracks.id", ondelete="CASCADE"),
+        nullable=False,
+        index=True,
+    )
+
+    # Additional metadata
+    notes: Mapped[str | None] = mapped_column(
+        String(1000),
+        nullable=True,
+        comment="User notes about the track",
+    )
+
+    # Timestamps
+    created_at: Mapped[datetime] = mapped_column(
+        default=datetime.utcnow,
+        nullable=False,
+    )
+    updated_at: Mapped[datetime] = mapped_column(
+        default=datetime.utcnow,
+        onupdate=datetime.utcnow,
+        nullable=False,
+    )
+
+    # Relationships
+    user: Mapped["User"] = relationship(
+        "User",
+        back_populates="liked_tracks",
+        lazy="selectin",
+    )
+    track: Mapped["Track"] = relationship(
+        "Track",
+        lazy="selectin",
+    )
+
+    # Table indices for optimal queries and uniqueness constraint
+    __table_args__ = (
+        Index("ix_liked_tracks_user_track", "user_id", "track_id", unique=True),
+    )
+
+    def __repr__(self) -> str:
+        return f"<LikedTrack user={self.user_id} track={self.track_id}>"
+
+    def to_dict(self) -> dict:
+        """Convert liked track model to dictionary."""
+        return {
+            "id": str(self.id),
+            "user_id": str(self.user_id),
+            "track_id": str(self.track_id),
+            "notes": self.notes,
+            "created_at": self.created_at.isoformat(),
+            "updated_at": self.updated_at.isoformat(),
+        }