Add Phase 4 Final Bugs Specification and Tests

- Introduced a new architecture specification for Phase 4 final bugs, detailing scope, decisions, runtime data contracts, action roles, execution lanes, speech ownership, and signal flow.
- Implemented changes in `scripts/action_registry.gd`, `scripts/action_editor.gd`, `scripts/sandbox_stage.gd`, `scripts/stage_gizmos.gd`, `scripts/stickman_factory.gd`, and `scripts/stickman_rig.gd` to address identified bugs.
- Created a new test suite `tests/test_phase4_final_bugs.gd` to validate the implementation, covering action roles, grid snapping, prop manipulation, reactive runtime lane, spawn pose preservation, and more.
- Added a unique identifier for the test file to ensure proper tracking and management.

scripts/action_registry.gd

@@ -7,6 +7,8 @@ extends RefCounted
 ## the ActionEditor and the panels generate their UI from this registry, so no
 ## other code changes are required.
 
+enum ReactiveRole { SEQUENTIAL, OVERLAY, TAKEOVER }
+
 const ACTION_TEMPLATES := {
 	"walk_to": {
 		"label": "Walk To",
@@ -14,6 +16,7 @@ const ACTION_TEMPLATES := {
 		"params": [
 			{ "key": "target", "type": "position", "required": true },
 		],
+		"reactive_role": ReactiveRole.SEQUENTIAL, "overlay_eligible": false,
 	},
 	"speak": {
 		"label": "Speak",
@@ -22,6 +25,7 @@ const ACTION_TEMPLATES := {
 			{ "key": "text", "type": "text", "required": true },
 			{ "key": "duration", "type": "float", "default": 2.0 },
 		],
+		"reactive_role": ReactiveRole.OVERLAY, "overlay_eligible": true,
 	},
 	"wait": {
 		"label": "Wait",
@@ -29,16 +33,19 @@ const ACTION_TEMPLATES := {
 		"params": [
 			{ "key": "duration", "type": "float", "required": true },
 		],
+		"reactive_role": ReactiveRole.SEQUENTIAL, "overlay_eligible": false,
 	},
 	"ragdoll": {
 		"label": "Ragdoll",
 		"icon": "💥",
 		"params": [],
+		"reactive_role": ReactiveRole.TAKEOVER, "overlay_eligible": false,
 	},
 	"recover": {
 		"label": "Recover",
 		"icon": "🔄",
 		"params": [],
+		"reactive_role": ReactiveRole.TAKEOVER, "overlay_eligible": false,
 	},
 }
 
@@ -66,6 +73,21 @@ static func icon(type: String) -> String:
 	return String(tpl.get("icon", ""))
 
 
+static func is_overlay_eligible(type: String) -> bool:
+	var tpl: Dictionary = ACTION_TEMPLATES.get(type, {})
+	return bool(tpl.get("overlay_eligible", false))
+
+
+static func reactive_role(action: Dictionary) -> ReactiveRole:
+	var type: String = String(action.get("type", ""))
+	var tpl: Dictionary = ACTION_TEMPLATES.get(type, {})
+	var role: ReactiveRole = int(tpl.get("reactive_role", ReactiveRole.SEQUENTIAL))
+	var params: Dictionary = action.get("params", {})
+	if type == "speak" and bool(params.get("stop_current", action.get("stop_current", false))):
+		return ReactiveRole.SEQUENTIAL
+	return role
+
+
 ## Converts a flat queue action into a rule-action shape (adds `target` + nests
 ## params). `target_id` is the acting stickman's instance id.
 static func to_rule_action(action: Dictionary, target_id: int) -> Dictionary:
@@ -76,6 +98,8 @@ static func to_rule_action(action: Dictionary, target_id: int) -> Dictionary:
 		"speak":
 			params["text"] = String(action.get("text", ""))
 			params["duration"] = float(action.get("duration", 2.0))
+			if bool(action.get("stop_current", false)):
+				params["stop_current"] = true
 		"wait":
 			params["duration"] = float(action.get("duration", 0.0))
 	return {
@@ -92,11 +116,14 @@ static func from_rule_action(rule_action: Dictionary) -> Dictionary:
 		"walk_to":
 			return { "type": "walk_to", "target": params.get("target", Vector2.ZERO) }
 		"speak":
-			return {
+			var speak: Dictionary = {
 				"type": "speak",
 				"text": String(params.get("text", "")),
 				"duration": float(params.get("duration", 2.0)),
 			}
+			if bool(params.get("stop_current", false)):
+				speak["stop_current"] = true
+			return speak
 		"wait":
 			return { "type": "wait", "duration": float(params.get("duration", 0.0)) }
 		_:
@@ -110,12 +137,17 @@ static func summarize(action: Dictionary) -> String:
 	var params: Dictionary = action.get("params", {})
 	match type:
 		"walk_to":
-			var t: Vector2 = action.get("target", params.get("target", Vector2.ZERO))
+			# Rule actions use top-level `target` for the actor instance id and
+			# nested `params.target` for the waypoint. Prefer the nested value and
+			# type-guard legacy/malformed payloads so summaries never crash.
+			var raw_target: Variant = params.get("target", action.get("target", Vector2.ZERO))
+			var t: Vector2 = raw_target as Vector2 if raw_target is Vector2 else Vector2.ZERO
 			return "Walk To (%d, %d)" % [int(roundf(t.x)), int(roundf(t.y))]
 		"speak":
 			var text := String(action.get("text", params.get("text", "")))
 			var dur := float(action.get("duration", params.get("duration", 2.0)))
-			return "Speak \"%s\" (%ss)" % [text, _fmt_duration(dur)]
+			var suffix: String = " — stops current" if bool(params.get("stop_current", action.get("stop_current", false))) else ""
+			return "Speak \"%s\" (%ss)%s" % [text, _fmt_duration(dur), suffix]
 		"wait":
 			var wd := float(action.get("duration", params.get("duration", 0.0)))
 			return "Wait %ss" % _fmt_duration(wd)