feat: Add VLC player API endpoints and associated tests

- Implemented VLC player API endpoints for playing and stopping sounds.
- Added tests for successful playback, error handling, and authentication scenarios.
- Created utility function to get sound file paths based on sound properties.
- Refactored player service to utilize shared sound path utility.
- Enhanced test coverage for sound file path utility with various sound types.
- Introduced tests for VLC player service, including subprocess handling and play count tracking.

app/models/sound_played.py

@@ -1,6 +1,6 @@
 from typing import TYPE_CHECKING
 
-from sqlmodel import Field, Relationship, UniqueConstraint
+from sqlmodel import Field, Relationship
 
 from app.models.base import BaseModel
 
@@ -14,18 +14,9 @@ class SoundPlayed(BaseModel, table=True):
 
     __tablename__ = "sound_played"  # pyright: ignore[reportAssignmentType]
 
-    user_id: int = Field(foreign_key="user.id", nullable=False)
+    user_id: int | None = Field(foreign_key="user.id", nullable=True)
     sound_id: int = Field(foreign_key="sound.id", nullable=False)
 
-    # constraints
-    __table_args__ = (
-        UniqueConstraint(
-            "user_id",
-            "sound_id",
-            name="uq_sound_played_user_sound",
-        ),
-    )
-
     # relationships
     user: "User" = Relationship(back_populates="sounds_played")
     sound: "Sound" = Relationship(back_populates="play_history")