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.

Docs/Architecture/05_building_block_view.md

@@ -25,7 +25,9 @@ C++ classes in `Game/GigLine/Source/GigLine/`:
 | `AGigLineShotActor` | Screenshot camera walker | Drives cameras in `-game` mode, `FScreenshotRequest`, quits |
 | `UGigLineAssetTools` | C++ collision helpers | `SetComplexCollisionAsSimple` on `StaticMesh` assets |
 
-Input assets in `/Game/Input/`: `IA_Move`, `IA_MoveBack`, `IA_Strafe`, `IA_StrafeLeft`, `IA_Look`, `IA_Jump`, `IA_Reset`, `IA_Pause`, bound in `IMC_Default`.
+Input assets in `/Game/Input/`: `IA_Move`, `IA_MoveBack`, `IA_Strafe`, `IA_StrafeLeft`, `IA_Look`, `IA_Jump`, `IA_Reset`, `IA_Pause`, `IA_ToggleCamera`, bound in `IMC_Default`.
+
+Player-facing bindings: **WASD** move, **mouse** look, **Space** jump, **R** reset, **Escape** pause, **V** swap first/third person. The camera and body work landed with `0.2.0` (see ADR-9): the shipped default view stays first person, and `-thirdperson` starts the pawn in the third-person rig — used by the screenshot run so the review is reproducible.
 
 ### Site
 

Docs/Architecture/09_architecture_decisions.md

@@ -55,3 +55,11 @@
 - **Decision**: All Blender work driven by Python scripts in `Tools/`. Skill packs used as method guides (checklists, naming, proportions) only.
 
 - **Consequences**: Scripts are version-controlled and repeatable. No live Blender session needed for CI.
+
+## ADR-9: Third-person body is an attachment of the first-person pawn, not a second pawn
+
+- **Context**: `0.2.0` needs a visible body and a third-person camera, while `0.1.0` shipped a first-person pawn with no body and the owner's decision was first person for that release. Two separate pawn classes would duplicate movement, input and reset logic, which is the code most likely to drift.
+
+- **Decision**: one pawn, both rigs. `AGigLineCharacter` carries a skeletal mesh (hidden in first person), a collision-tested spring-arm camera, and a **V** toggle that swaps the active camera and the body's visibility. The shipped default view stays first person; `-thirdperson` starts the pawn in the third-person rig and is what the screenshot run passes, so the review shot is reproducible without a human pressing a key.
+
+- **Consequences**: movement, reset, pause and the QA self-test stay in one place. The body's animation state is driven from `Tick` by speed rather than from input, so being pushed or falling animates correctly. The cost is that the camera swap is not a separate actor, so a future cinematic camera needs its own path rather than reusing the toggle.

Docs/Architecture/architecture.md

@@ -169,7 +169,9 @@ C++ classes in `Game/GigLine/Source/GigLine/`:
 | `AGigLineShotActor` | Screenshot camera walker | Drives cameras in `-game` mode, `FScreenshotRequest`, quits |
 | `UGigLineAssetTools` | C++ collision helpers | `SetComplexCollisionAsSimple` on `StaticMesh` assets |
 
-Input assets in `/Game/Input/`: `IA_Move`, `IA_MoveBack`, `IA_Strafe`, `IA_StrafeLeft`, `IA_Look`, `IA_Jump`, `IA_Reset`, `IA_Pause`, bound in `IMC_Default`.
+Input assets in `/Game/Input/`: `IA_Move`, `IA_MoveBack`, `IA_Strafe`, `IA_StrafeLeft`, `IA_Look`, `IA_Jump`, `IA_Reset`, `IA_Pause`, `IA_ToggleCamera`, bound in `IMC_Default`.
+
+Player-facing bindings: **WASD** move, **mouse** look, **Space** jump, **R** reset, **Escape** pause, **V** swap first/third person. The camera and body work landed with `0.2.0` (see ADR-9): the shipped default view stays first person, and `-thirdperson` starts the pawn in the third-person rig — used by the screenshot run so the review is reproducible.
 
 ### Site