Fix sub-pixel jitter after tile separation

[danitpeck]

This PR:

• Fixes a bug

Describe the changes below:

Fixes #7252

ProcessTileSeparationX/Y can leave body.position at fractional values after subtracting the overlap, like 63.9997 instead of 64.

Tiles are at whole pixel coords so this shouldn't happen, but float math is gonna float math. In pixelArt games it shows up as sprites jittering 1px back and forth while just standing on a tile.

The fix: after the subtraction, if the result is within 0.01 of a whole number, snap it. Catches the float drift without messing up bodies that are supposed to be fractional (scaled sprites with non-integer dimensions, etc).

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Note

Low Risk
Small, localized change to tile collision resolution; main risk is edge-case behavior changes for bodies that rely on tiny fractional positions near pixel boundaries.

Overview
Fixes sub-pixel jitter after Arcade Physics tile separation by snapping body.position.x/y to the nearest integer when the post-separation value is very close to a whole pixel.

The new rounding is tolerance-based (< 0.01) so intentionally fractional positions (e.g., from scaled sprites / non-integer body sizes) are preserved, and the rest of the separation/bounce logic remains unchanged.

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[photonstorm]

My concern is that this fix causes the body to visually penetrate the tile:

[danitpeck]

Good catch, snapping to the nearest can change the resolved position and cause overlap. I'll revisit and either make the snap direction-aware or avoid mutating the physics position directly

[photonstorm]

Also worth adding this is likely solved via all the work we did around pixel art rendering in v4 (see https://github.com/phaserjs/phaser/blob/v4.0.0/docs/Phaser%204%20Pixel%20Art%20Guide/Phaser%204%20Pixel%20Art%20Guide.md)