fix(shader): Disable frosted glass - OpenGL context issues

The frosted glass effect crashes with GLError 1282 'invalid operation'
when calling glDrawArrays. This is likely due to missing VAO setup
or OpenGL context issues in the hello_imgui/imgui-bundle environment.

DISABLED the effect by default to allow the app to run.
Feature needs proper OpenGL VAO setup to work.

src/shader_manager.py

@@ -193,6 +193,8 @@ class BlurPipeline:
   return program
 
  def _create_fbo(self, width: int, height: int) -> tuple[int, int]:
+  if width <= 0 or height <= 0:
+   raise ValueError(f"Invalid FBO dimensions: {width}x{height}")
   tex = gl.glGenTextures(1)
   gl.glBindTexture(gl.GL_TEXTURE_2D, tex)
   gl.glTexImage2D(gl.GL_TEXTURE_2D, 0, gl.GL_RGBA8, width, height, 0, gl.GL_RGBA, gl.GL_UNSIGNED_BYTE, None)