feat: Implement Live Director System for interactive simulation control

- Added waypoint context updates to handle action queue statuses in `waypoint_context.gd`.
- Introduced new scene file `manwalk.scene` with terrain and stickman setup.
- Created architecture summary for the Live Director System detailing core state transitions, physics mechanics, UI elements, and action execution.
- Specified class contracts and interfaces for the Live Director implementation in `phase_12_live_director.md`.
- Defined state transitions, input handling, and queue editing mechanics for the Live Director feature.

README.md

@@ -34,6 +34,24 @@ No CLI build, test, or lint commands are used. Run the project from the Godot ed
 
 The main scene is configured as `run/main_scene="res://scenes/stickman_editor.tscn"` in `project.godot`.
 
+### Sandbox Stage (F6)
+
+Run `res://scenes/sandbox_stage.tscn` with **F6** to build and direct a scene. **EDIT** is for
+placing and transforming stage objects. **DIRECT** is for authoring stickman actions and event
+rules. Press **Space** or **Play** to start a run; press Space or **Direct** to freeze it.
+Space acts on each key press, so holding it does not repeatedly toggle the run. **Play** or Space
+resumes a paused run from its frozen pose and time. The stage clock is visible in the top bar as
+minutes, seconds, and centiseconds; it shows `00:00.00` in EDIT and planning DIRECT.
+
+While a run is paused in DIRECT, you can add or edit stickman actions and event rules against the
+paused scene. Pending actions can be reordered among themselves; the active action stays fixed.
+Completed or interrupted actions can be deleted, with deletion taking effect on the next run from
+`t = 0`. Event rules are not reordered. Objects cannot be moved or placed while paused; return to
+EDIT for object changes. **Reset** or entering EDIT restores authored object transforms and time
+zero while keeping action and rule edits. Paused edits autosave after a short debounce. A paused
+walk or recovery resumes with its animation/tween phase intact; recovery does not start a second
+ragdoll, and recovered feet keep their IK targets aligned instead of crossing.
+
 ## Quick Start
 
 ### 1. Create a body part