gameplay: walkable demo map, reset and pause

Tools/ue_build_demo_map.py builds /Game/Hollywood/DemoMap: sun, sky, the hero
facade on the building line, six site meshes imported with collision, and a
player start on the north sidewalk. Tools/ue_import_site.py imports the site
FBXs; terrain, road and sidewalks use complex-as-simple so a simple hull cannot
ramp over the kerbs. Art/blender/site/export_site_fbx.py exports one FBX per
object so each can carry its own collision.

Reset (R) and pause (Escape) join the character and the input context: reset
restores the spawn transform and clears momentum, pause is a real game pause that
releases the cursor. DefaultInput.ini captures the mouse on launch.

Three placement defects found by measuring the imported actors rather than
trusting the plan: the spawn was on the wrong sidewalk because the FBX flip
inverts north, a mirror I added to the exporter double-corrected an already
correct sidewalk, and the street meshes only carry part of the north walk - the
rest is terrain.

Tools/ue_build_review_map.py

@@ -182,6 +182,43 @@ try:
         # oblique from the north-west, reading the colonnade in depth
         ("hero-facade-oblique", unreal.Vector(hero_x - 2200, -3400, 620), unreal.Vector(hero_x + 300, hero_y, 700)),
     ]
+    # --- demo map views: what the player actually sees ----------------------
+    demo = unreal.EditorAssetLibrary.load_asset("/Game/Hollywood/DemoMap")
+    if demo and unreal.EditorAssetLibrary.does_asset_exist("/Game/Hollywood/DemoMap"):
+        # The demo map has terrain, street, sidewalks and the facade; the review
+        # floor does not. Load it, stage the shot cameras, save, then restore the
+        # review map so the rest of the run is unaffected.
+        unreal.EditorLevelLibrary.load_level("/Game/Hollywood/DemoMap")
+        for actor in unreal.EditorLevelLibrary.get_all_level_actors():
+            if actor.get_actor_label() == "ShotSequencer":
+                unreal.EditorLevelLibrary.destroy_actor(actor)
+        # Unreal signs, measured from the imported site meshes: north sidewalk at
+        # Y -1912..-1053, road -1382..+1047, south sidewalk +718..+1447, facade at
+        # Y -1450. So "opposite the facade" is Y -1650 and the view faces -Y.
+        demo_shots = [
+            # 14 m back so the 14.5 m elevation fits: at 2 m the camera sees only
+            # the colonnade's underside.
+            ("demo-spawn-view", unreal.Vector(-10722.5, -3500, 165), unreal.Vector(-10722.5, -1450, 700)),
+            ("demo-street-level", unreal.Vector(-11000, -400, 165), unreal.Vector(-10722.5, -1450, 500)),
+            ("demo-crossing", unreal.Vector(-13600, -1650, 165), unreal.Vector(-12722.5, -1450, 500)),
+        ]
+        seq = spawn(unreal.GigLineShotActor, unreal.Vector(0, 0, 300), "ShotSequencer")
+        if seq:
+            seq.set_editor_property("shot_locations", [c[1] for c in demo_shots])
+            seq.set_editor_property("shot_rotations",
+                                    [unreal.MathLibrary.find_look_at_rotation(c[1], c[2]) for c in demo_shots])
+            seq.set_editor_property("shot_names", [c[0] for c in demo_shots])
+            seq.set_editor_property("quit_when_done", False)
+        saved = unreal.EditorLoadingAndSavingUtils.save_map(
+            unreal.EditorLevelLibrary.get_editor_world(), "/Game/Hollywood/DemoMap")
+        log(f"demo map staged: {len(demo_shots)} cameras, save {saved}")
+        unreal.EditorLevelLibrary.load_level("/Game/Test/ReviewMap")
+        for actor in unreal.EditorLevelLibrary.get_all_level_actors():
+            if actor.get_actor_label() == "ShotSequencer":
+                unreal.EditorLevelLibrary.destroy_actor(actor)
+    else:
+        log("MISSING: /Game/Hollywood/DemoMap (run Tools/ue_build_demo_map.py)")
+
     shots = spawn(unreal.GigLineShotActor, unreal.Vector(0, 0, 300), "ShotSequencer")
     if shots:
         shots.set_editor_property("shot_locations", [c[1] for c in cams])