feat(camera): third-person rig, V toggle, visible body

One pawn, both rigs (ADR-9): a skeletal body hidden in first person, a
collision-tested spring arm, and a toggle that swaps the active camera and the
body's visibility. Shipped default stays first person; -thirdperson starts the
pawn in the third-person rig so the review shot is reproducible, and the
screenshot run passes it.

Three defects found and two fixed:
- The skin material had no SkeletalMesh usage flag, so Unreal silently substituted
  the default grey. That is why the body rendered as clay.
- render_screenshots.sh still called ./Engine/... on this branch (the fix lives on
  the facade branch and never reached main); applied here so the shots generate.
- OPEN: the idle clip is bound and PlayAnimation is called - the run logs the clip
  name - but the body still renders in bind pose, arms out. Recorded with that
  evidence in TODO.md rather than called done.

Shot 5 (demo-third-person) added and documented; camera collision is implemented
but unproven, since the spawn has open space behind it.

Screenshots/README.md

@@ -22,6 +22,7 @@ Each shot has an **expectation** in [`Tools/visual_targets.json`](../Tools/visua
 | 2 | `demo/review-demo-street-level.png` | eye height, north side | Street level: the hero colonnade with the adjacent frontage buildings either side, shopfronts at pavement level | ☑ 2026-11-09 | ☑ 2026-11-09 |
 | 3 | `demo/review-demo-crossing.png` | along the crosswalk | The designated mid-block crossing (s=130 m, UE X −14956): zebra bars on the asphalt, south frontage and colonnade behind | ☑ 2026-11-09 | ☑ 2026-11-09 |
 | 4 | `demo/review-demo-north-buildings.png` | across the Boulevard | The two north-side buildings (TCL Chinese Theatre, Madame Tussaud's) from the south side, full height in frame | ☑ 2026-11-09 | ☑ 2026-11-09 |
+| 5 | `demo/review-demo-third-person.png` | third-person boom, 6 m behind the pawn | The player's own visible body on the north sidewalk, seen from behind, with the hero façade across the street. Captured with `-thirdperson`, which starts the pawn in the third-person rig | ☑ 2026-11-09 | ☐ pending |
 
 Approval is per shot, in the table above (owner review of the `0.1.4` set, recorded in [`Docs/reviews/0.1.4-review.md`](../Docs/reviews/0.1.4-review.md)). Add a row when a shot is added; remove the file in the same change when a shot is retired.
 
@@ -49,3 +50,17 @@ Note the comparison is only meaningful when the shot and the reference frame the
 - Banners sit on the column line rather than flush to the wall (they hang on the columns in the photographs, so this is acceptable).
 - Between kerb and building line the walkable surface is the terrain mesh, not a modelled pavement.
 - The El Capitan Theatre has no marquee or blade sign yet — the feature that makes it read as itself.
+
+## 0.2.0 third-person body — what to look at
+
+Shot 5 is the review for the third-person rig. It is **not** a finished body: the figure is in bind pose, arms out.
+
+What is implemented and visible:
+
+- The pawn carries a visible skeletal body with the warm skin material (the material needed `used_with_skeletal_mesh=True`; without it Unreal silently substituted the default grey, which is what the first render showed).
+- A spring-arm camera with collision testing, and a **V** toggle between first and third person. The shipped default stays first person; the review passes `-thirdperson` so the shot is reproducible.
+
+What is **not** working, with evidence:
+
+- The idle clip is bound and `PlayAnimation` is called — the run logs `GigLine: playing body clip Character_AnimHuman_rig_GigLine_Idle` — but the body still renders in bind pose. The clip therefore is not deforming the mesh; that is the open defect, tracked in `TODO.md` under "Verify animation plays correctly on the imported rig".
+- The arms-down offsets are baked into the clips as a base on top of the A-pose bind (`BASE` in `Tools/character_anim_build.py`), so a correct playback should show arms down. Seeing them out is the same defect, not a missing offset.