qa fix (wip): input assets hard-referenced, static site collision, spawn on sidewalk

Carries the QA fixes for the walkable demo off main onto an error-fixing
branch so a live window can be tested without blocking the clean main.

- GigLineCharacter: hard-reference the Enhanced Input assets via
  ConstructorHelpers so the cooker includes /Game/Input (they were soft-only
  and pruned from the pak -> no inputs bound). Push the mapping context on a
  deferred timer after possession.
- defaultgame.ini: +DirectoriesToAlwaysCook for /Game/Input, Hollywood, Test.
- ue_build_demo_map.py: stage site meshes STATIC with explicit collision
  (QUERY_AND_PHYSICS, WorldStatic, BlockAll); hero facade STATIC; PlayerStart
  moved onto the north sidewalk at Y -1200.
- DemoMap.umap rebuilt with the above.

STATUS: packaged build now logs all input assets ok and grounded=1/Walking,
so falling + input-nil are fixed in the package; the user still hit a stuck
window (no mouse/keys) in one test, so this remains WIP pending a clean
interactive run.

Game/GigLine/Config/DefaultGame.ini

@@ -7,6 +7,15 @@ CopyrightNotice=
 BuildConfiguration=PPBC_Development
 FullRebuild=False
 UsePakFile=True
+; Runtime-loaded content must ship even when nothing statically references it.
+; The Enhanced Input assets are only soft-loaded by AGigLineCharacter at
+; BeginPlay; without this the cooker prunes them from the pak (observed: the
+; cook ReferencedSet had zero /Game/Input entries, so inputs were all nil and
+; no keys worked). Always cook the demo map + input. Keep both maps listed so
+; EditorStartupMap/GameDefaultMap selection stays flexible.
++DirectoriesToAlwaysCook=/Game/Input
++DirectoriesToAlwaysCook=/Game/Hollywood
++DirectoriesToAlwaysCook=/Game/Test
 
 [/Script/EngineSettings.GameMapsSettings]
 ; Temporary default while the demo map is being built; GameMapsSettings in