Players reported targeting "feels inconsistent" because the server
PrototypeTargetRegistry anchors (alpha (-5,-5) r=8, beta (8,8) r=4) have
no visible meshes — the only console visible in the scene is the NEO-9
PrototypeTerminal at origin, which is unrelated to NEO-23/24 targeting.
Adds a display-only mirror of the server registry:
- client/scripts/prototype_target_markers.gd spawns a colored mast +
translucent flat radius ring per anchor so the lock radius is
visible in-world.
- client/scripts/prototype_target_constants.gd gains ANCHORS with
position/radius/color, matching PrototypeTargetRegistry.cs. Marked
display-only; server remains authoritative for validity.
- TargetLockLabel now renders a per-anchor distance line each physics
tick ("<id>: <d> m / <radius> (in|out)") so players can see the
relationship between the visible capsule and the lock radius and
immediately spot client/server position drift.
Also updates README, plan (Decision 4), manual QA (Section 1 boot +
Section 4 locomotion), and the review file's follow-up section to
describe the UX fix.
