初始提交：3 款纯音频游戏 + 共享引擎 + 完整文档与资产管线

- 共享引擎（app/src/main）：GestureEngine 6 手势识别、AudioEngine 三层音频
  （ExoPlayer BGM 交叉淡入 / 对白 ducking / SoundPool 低延迟）、Game/GameEngine
  状态机接口、MainActivity 全屏封面 + TalkBack
- 《声命线》storyline：末世互动广播剧，3 幕 8 抉择点 4 结局
- 《声东击西》reflex：听声辨位反应，12 波战斗 + BGM 三档 BPM 变速
- 《暗室》escape：3x3 网格密室逃脱，钥匙→铁柜→保险丝→电箱→大门谜题链
- 文档：setup（从零搭建）/ architecture（架构）/ engine-api（引擎 API）/
  asset-pipeline（资产流水线）/ games/*（三款游戏设计文档）
- 资产管线：Qwen3-TTS 对白 + 程序合成音效/BGM + Mureka BGM 的 gen 脚本与台账，
  全部 ogg 资产入库可复现
- env.d 环境脚本：android/tts 入库；sfx/mureka 含密钥不入库，仅提交 .example.sh 模板

tools/stable-audio-3/optimized/tensorRT/build/_arch.py

@@ -0,0 +1,73 @@
+"""Shared helpers for the build scripts: GPU arch detection + output paths.
+
+Every builder writes its TRT engine to:
+    ../models/<arch>/<engine_subdir>/<file>.trt
+
+where <arch> is the sm_XX compute capability of the GPU you're building on
+(TensorRT bakes the arch into the engine, so the arch you build on IS the
+arch the engine runs on).
+"""
+import os
+import subprocess
+
+
+def detect_arch() -> str:
+    """Compute capability of the current GPU as 'sm_XX' (e.g., 'sm_90').
+
+    Reads nvidia-smi. Falls back to 'sm_90' if no GPU is visible (the build
+    will fail anyway, but you get a clearer error from TensorRT than from us).
+    """
+    try:
+        out = subprocess.check_output(
+            ["nvidia-smi", "--query-gpu=compute_cap", "--format=csv,noheader,nounits"],
+            stderr=subprocess.DEVNULL, timeout=5,
+        ).decode().strip().splitlines()
+        if out:
+            return f"sm_{out[0].strip().replace('.', '')}"
+    except Exception:
+        pass
+    return "sm_90"
+
+
+def repo_root() -> str:
+    """Path to the optimized/tensorRT/ directory (parent of build/)."""
+    return os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
+
+
+def arch_dir(arch: str = None) -> str:
+    """Resolve the per-arch output dir for engines: ../models/<arch>/."""
+    if arch is None:
+        arch = detect_arch()
+    d = os.path.join(repo_root(), "models", arch)
+    os.makedirs(d, exist_ok=True)
+    return d
+
+
+def onnx_dir(engine_subdir: str = None) -> str:
+    """ONNX output dir. ONNX is arch-independent — the same .onnx file can be
+    compiled into a .trt engine for any TRT-supported GPU.
+
+    Resolution order:
+      1. $SA3_ONNX_DIR (override; used by automation)
+      2. ../../../../stable-audio-3-optimized/onnx/  — the HF model repo when
+         checked out as a sibling of stable-audio-3 (canonical layout: github
+         repo = code, HF repo = ONNX + TRT artifacts)
+      3. <github_repo>/optimized/tensorRT/onnx/      — local fallback when no
+         HF clone is around (a working area; not git-tracked here)
+    """
+    override = os.environ.get("SA3_ONNX_DIR")
+    if override:
+        d = override
+    else:
+        # repo_root() = .../stable-audio-3/optimized/tensorRT
+        # HF sibling  = .../stable-audio-3-optimized
+        github_root = os.path.dirname(os.path.dirname(os.path.dirname(repo_root())))
+        hf_sibling = os.path.join(github_root, "stable-audio-3-optimized", "onnx")
+        if os.path.isdir(os.path.dirname(hf_sibling)):
+            d = hf_sibling
+        else:
+            d = os.path.join(repo_root(), "onnx")
+    if engine_subdir:
+        d = os.path.join(d, engine_subdir)
+    os.makedirs(d, exist_ok=True)
+    return d