[TRACKER] Ray casting related issues

[Xrayez]

Godot version:
3.2, 4.0+

Issue description:
I've been seeing various raycast issues popping up here recently, some of them share a lot of similarities so it's worth to track and potentially discuss those issues in a holistic way, and perhaps pin-point some duplicates.

Tasks

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1. Raycast2d does not collide with CircleShape2d in CollisionShape2d, but does work with RectangleShape2d. #39859
   bug confirmed topic:physics +3
2. RayCast2D and CollisionPolygon2D collisions are unreliable #38873
   bug topic:physics +2
3. Inconsistent RayCast2D collision results for different shapes #38343
   bug topic:physics +2
4. [Bullet] RayCast.get_collider_shape() doesn't actually return Shape ID #37985
   documentation enhancement topic:physics +3
5. RayCast2D behaves erratically if a lot of exceptions are added #37736
   bug topic:physics +2
6. RayCast2D will not collide with TileMap if it's fully inside tile #36259
   bug topic:physics +2
7. intersect_ray() result normal can be inverted or length 0. #35845
   bug topic:physics +2
8. Tilemap world_to_map() does not get the correct tile in combination with Raycast2D #35344
   discussion +1
9. Why raycasts are disabled by default? #31637
   breaks compat discussion topic:physics +3
10. [Bullet] Raycasting a BoxShape hints round edges/artifacts #28032
    bug confirmed topic:3d topic:physics +4
11. PhysicsDirectSpaceState intersect_ray exclude does not work with GridMaps #27282
    discussion enhancement topic:3d topic:physics +4
12. Raycast3D is very hard to see in editor #19793
    enhancement topic:editor topic:rendering usability +4
13. intersect_ray() becomes flaky if a flat CollisionShape exists anywhere #41031
    bug topic:physics +2
14. Raycast can collide with area even if monitorable property is set to false #41155
    discussion topic:physics +2
15. Raycasts inside Tilemaps only collide at the edge. #44003
    bug topic:physics +2
16. RayCast still Detects Disabled CollisionShapes #49778
    bug topic:3d topic:physics +3
17. Hardcoded maximum ray distance when Viewport processes 3d object picking #49735
    discussion enhancement topic:3d topic:core +4

Connections

#37736, #38343, #38873, #39859: all report inconsistent collision results. #38343 provides a table of various entering/exiting/internal conditions for different shapes.