feat(anim): idle and walk clips on the MPFB rig

Two parametric cycles authored at 30 fps instead of hand-keyed poses, so the loop
closes by construction: GigLine_Idle (60 f, breathing sway, feet planted) and
GigLine_Walk (30 f, one stride, hip 0.45 rad / knee 0.55 / arm 0.32, arms
counter-phased, torso counter-rotation).

The limb axes were measured, not assumed: a probe rotated upperleg01.L by 0.5 rad
on each axis and read foot.L, which moved -0.022 -> +0.362 in Y on X, twisted on Y
and abducted on Z. Using the wrong axis here would have produced a character
scissoring sideways, which no import error would have caught.

The character export preset now bakes animation. Without bake_anim the exporter
writes a static bind pose and Unreal imports a mesh with no AnimSequence and no
error, so the importer asserts a clip exists and prints VERDICT: PASS/FAIL.

Verified in /Game/Test/Character: Idle 1.967 s and Walk 0.967 s, both AnimSequences,
skeleton intact. Playback on a possessed pawn is not yet verified: the demo pawn has
no visible body, so that check belongs with the third-person camera item.

Tools/README.md

@@ -42,6 +42,7 @@ Geographic tools live in [`Geo/tools/`](../Geo/README.md) and the Blender-side b
 | Tool | Purpose |
 | --- | --- |
 | `hero_facade_build.py` | Parametric hero façade; emits a JSON report naming the evidence behind every part |
+| `character_anim_build.py` | Authors the basic animation set on the MPFB rig — `GigLine_Idle` (60 f) and `GigLine_Walk` (30 f) sampled from parametric cycles at 30 fps — and exports one animated FBX with the `ue_character_v1` preset. Rotation axes are measured on the rig, not assumed (probe in the docstring). `--out`, `--report`. |
 | `mpfb_character_export.py` | MPFB human, standard rig, baked skin, FBX export |
 
 ## Unreal import and level building
@@ -53,6 +54,7 @@ Geographic tools live in [`Geo/tools/`](../Geo/README.md) and the Blender-side b
 | `ue_build_demo_map.py` | Builds `/Game/Hollywood/DemoMap`: lighting, façade, site meshes, player start |
 | `ue_build_review_map.py` | Rebuilds `Test/ReviewMap`, stages the shot camera list, and stages the demo-map views |
 | `ue_create_input_assets.py` | Creates `/Game/Input` actions and the mapping context headlessly |
+| `ue_character_anim_import.py` | Imports the animated FBX into `/Game/Test/Character` and **verifies an AnimSequence exists** — an FBX exported without `bake_anim` imports a mesh and no clips, with no error. Writes `VERDICT: PASS/FAIL` to `/tmp/gigline/character-anim-import.txt`. |
 | `ue_character_import.py` | Skeletal import plus the material/texture chain Interchange skips |
 
 ## Visual review