feat: 重组为标准 skill 包结构 + 修复 verify.sh bash 3.2 兼容

- 新增 .claude/skills/new-project/SKILL.md（标准 skill 格式）
- install-skill.sh 安装时组装 SKILL.md + verify.sh，单一源无重复
- verify.sh 改用索引数组替代 declare -A，兼容 macOS bash 3.2
- log_pass/log_skip 显式 return 0，避免 set -e 下非 verbose 误退出
- README 改为 skill 优先；补全 copier.yml/scripts/template 入库

template/backend/src/main.py.jinja

@@ -0,0 +1,27 @@
+from fastapi import FastAPI
+from loguru import logger
+
+from .core.config import get_settings
+from .core.logging import configure_logging
+
+settings = get_settings()
+configure_logging(settings.log_level)
+
+app = FastAPI(
+    title="{{ project_name }} Backend",
+    docs_url="/docs" if settings.enable_api_docs else None,
+    redoc_url="/redoc" if settings.enable_api_docs else None,
+    openapi_url="/openapi.json" if settings.enable_api_docs else None,
+)
+
+
+@app.get("/health")
+async def health() -> dict[str, str]:
+    return {"status": "ok"}
+
+
+if __name__ == "__main__":
+    import uvicorn
+
+    logger.info("Starting backend | port={}", settings.port)
+    uvicorn.run("src.main:app", host="0.0.0.0", port=settings.port, reload=True)