feat: 重构 Docker 配置结构，添加 compute 模块及新增文档

- 将 Dockerfile 和 docker-compose.yml 迁移至 docker/ 目录下统一管理
- 新增 compute 计算模块（API 入口、依赖配置）
- 新增 docker/app 和 docker/compute 部署配置
- 新增 demo-development-plan.md 演示开发计划文档
- 更新后端 API 设计、部署计划、架构需求等文档
- 更新 postgres 数据库 schema

Co-Authored-By: Claude <noreply@anthropic.com>

compute/api/main.py

@@ -0,0 +1,40 @@
+from __future__ import annotations
+
+import os
+from pathlib import Path
+
+from fastapi import FastAPI
+
+
+def create_app() -> FastAPI:
+    app = FastAPI(title="YG Fine-Tune Compute API")
+
+    @app.get("/health")
+    async def health_check() -> dict[str, str]:
+        return {
+            "status": "ok",
+            "compute_host_id": os.getenv("COMPUTE_HOST_ID", "unknown"),
+        }
+
+    @app.get("/api/v1/compute/health")
+    async def compute_health_check() -> dict[str, str | bool]:
+        data_root = Path(os.getenv("YG_FT_DATA_ROOT", "/data/yg-ft"))
+        llama_factory_home = Path(os.getenv("LLAMA_FACTORY_HOME", "/opt/LLaMA-Factory"))
+        return {
+            "status": "ok",
+            "compute_host_id": os.getenv("COMPUTE_HOST_ID", "unknown"),
+            "app_callback_enabled": os.getenv("ENABLE_APP_CALLBACK", "false").lower() == "true",
+            "data_root": str(data_root),
+            "data_root_exists": data_root.exists(),
+            "llama_factory_home": str(llama_factory_home),
+            "llama_factory_home_exists": llama_factory_home.exists(),
+        }
+
+    @app.get("/api/v1/compute/jobs")
+    async def list_jobs() -> dict[str, list[dict[str, str]]]:
+        return {"items": []}
+
+    return app
+
+
+app = create_app()