Point light flickering / pop-out pop-in issues 0.19

## Bevy version and features

0.19

## What you did

Ported 0.18 -> 0.19

Video here: https://www.youtube.com/watch?v=jUOMN9ljy8Y

You can see point light popping in and out and in again, even when "just" zooming in. Visible in many places in the above video. Not happening in 0.18.

## What went wrong

Point lights disappearing and re-appearing.

## Additional information

_Camera_

Camera3d + Projection::Orthographic: scale: 0.02, ScalingMode::FixedVertical { viewport_height: 1080.0 }, near: -500.0
Transform: positioned at (25, 25, 25), looking_at(Vec3::ZERO, Vec3::Y) — 45° azimuth, ~35° elevation isometric
Also on the camera: Bloom::default(), DepthPrepass, EnvironmentMapLight, HDR default

_Point light_

PointLight { intensity: 12000.0, range: 4.5, shadow_maps_enabled: false, ..default() }
Positioned 0.45 units above a terrain mesh surface (custom heightmap mesh, rendered with an ExtendedMaterial splat shader)
Its color is animated each frame between two colors (e.g. srgb(0.20, 0.80, 1.00) ↔ srgb(0.10, 0.40, 0.90)), full cycle every 8 s

Reproduce the issue in Bevy 0.19 using the described orthographic camera, terrain mesh, animated point light, and rendering features, then compare the result with Bevy 0.18. Trace the point-light rendering and visibility behavior involved in the pop-in; done means the light remains consistently visible while zooming and the regression is covered by a test or reproducible case.

Written by the indexing model from the issue text.