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.

Game/GigLine/Source/GigLine/GigLineCharacter.h

@@ -34,6 +34,19 @@ protected:
 	/** Loads the Enhanced Input assets from /Game/Input; called from BeginPlay. */
 	void LoadInputAssets();
 
+	/** Teleports back to the map's PlayerStart and clears velocity. */
+	void ResetToStart();
+	void TogglePause();
+
+	/** Where the player started, so reset returns there rather than the origin. */
+	UPROPERTY()
+	FVector StartLocation = FVector::ZeroVector;
+
+	UPROPERTY()
+	FRotator StartRotation = FRotator::ZeroRotator;
+
+	bool bPaused = false;
+
 	/** Moves along the control yaw by the given forward/strafe amounts. */
 	void ApplyMove(float Forward, float Strafe);
 
@@ -69,6 +82,14 @@ protected:
 	UPROPERTY(EditDefaultsOnly, BlueprintReadOnly, Category = "Input")
 	TObjectPtr<UInputAction> JumpAction;
 
+	/** Respawn at the start point (R). */
+	UPROPERTY(EditDefaultsOnly, BlueprintReadOnly, Category = "Input")
+	TObjectPtr<UInputAction> ResetAction;
+
+	/** Toggle the pause menu (Escape). */
+	UPROPERTY(EditDefaultsOnly, BlueprintReadOnly, Category = "Input")
+	TObjectPtr<UInputAction> PauseAction;
+
 	UPROPERTY(VisibleAnywhere, BlueprintReadOnly, Category = "Camera")
 	TObjectPtr<UCameraComponent> FirstPersonCamera;