feat(playable): 首个 Mac 联网内测版 STB-01 soak 工具与发布状态文档

- 新增 script/playable_soak.sh：先做 soak 配置/资源校验，无 --allow-gameplay
  只校验不启动客户端；N(>=10) 次独立正常退出运行 + 墙钟 soak，失败即停止后续
  运行并记 BLOCKED；写本批次 release-manifest.json 后聚合
- run_client_gate.sh：确认的故障代理对所有 suite 启动（共享场景的退出运行也经代理）；
  soak 超时下限只约束 soak 客户端（validate_soak 增加 soak_client 参数）
- 新增本地 127.0.0.1 故障代理、RSS 采样/内存判定、窗口/指标/流程模块及其测试
- forest_mob_render_test 输出 PASS/FAIL 标记，供 rendering_batch_test.sh 识别
- 新增 docs/FIRST-MAC-PLAYABLE-STATUS.md：如实记录 PASS/BLOCKED、已知问题与环境需求
- .gitignore 排除本地场景配置、凭据文件与运行输出

离线回归：rendering_batch_test.sh failures=0，playable_gate_test.sh PASS，
node 夹具测试 PASS。未联网运行，未重建候选包。

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Ft3kXpNdLbKEfg5uDLfqVF

project/fx/effect_player.gd

@@ -29,6 +29,10 @@ var _light_states: Array[Dictionary] = []
 var _bsphere_r := 0.0
 var _playing := false
 var _cleanup_remaining := -1.0
+## MSE-defined playback length of the last play(); -1 while looping (owner-bound).
+var defined_lifetime_ms := -1
+## Why the node left the tree: "cleanup" when its own playback clock freed it.
+var finish_reason := ""
 
 static var _glow_tex: Texture2D
 
@@ -64,6 +68,7 @@ func _process(delta: float) -> void:
 	if _cleanup_remaining >= 0.0:
 		_cleanup_remaining -= maxf(delta, 0.0)
 		if _cleanup_remaining <= 0.0:
+			finish_reason = "cleanup"
 			queue_free()
 
 func play(force_one_shot := false) -> void:
@@ -71,6 +76,7 @@ func play(force_one_shot := false) -> void:
 	# may start or delete an effect after stop/replay, or while it is paused.
 	_playing = true
 	_cleanup_remaining = maxf(_longest_life() + 0.5, 1.5) if (force_one_shot or one_shot) else -1.0
+	defined_lifetime_ms = roundi(_longest_life() * 1000.0) if (force_one_shot or one_shot) else -1
 	for state in _particle_states:
 		state["clock"] = 0.0
 		state["emission_stopped"] = false
@@ -97,6 +103,7 @@ func stop() -> void:
 	# Existing particles may finish their lifetime; mesh/light emission stops now.
 	_playing = false
 	_cleanup_remaining = -1.0
+	defined_lifetime_ms = -1
 	for e in _emitters:
 		e.emitting = false
 	for mesh in _mesh_nodes: