fix config model: remove ge=0 constraints from LoggingConfig

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

src/server/models/config.py

@@ -125,10 +125,10 @@ class LoggingConfig(BaseModel):
         default=None, description="Optional file path for log output"
     )
     max_bytes: Optional[int] = Field(
-        default=None, ge=0, description="Max bytes per log file for rotation"
+        default=None, description="Max bytes per log file for rotation"
     )
     backup_count: Optional[int] = Field(
-        default=3, ge=0, description="Number of rotated log files to keep"
+        default=3, description="Number of rotated log files to keep"
     )
 
     @field_validator("level")