Initial commit: Pixel AI comic/video creation platform

- FastAPI backend with SQLModel, Alembic migrations, AgentScope agents
- Next.js 15 frontend with React 19, Tailwind, Zustand, React Flow
- Multi-provider AI system (DashScope, Kling, MiniMax, Volcengine, OpenAI, etc.)
- All HTTP clients migrated from sync requests to async httpx
- Admin-managed API keys via environment variables
- SSRF vulnerability fixed in ensure_url()

backend/src/config/services/moonshot/llm.json

@@ -0,0 +1,11 @@
+{
+    "base_url": "https://api.moonshot.cn/v1",
+    "kimi-k2.5": {
+        "name": "Kimi 2.5",
+        "class": "backend.src.services.provider.openai_service.OpenAIService",
+        "args": [
+            "kimi-k2.5"
+        ],
+        "enabled": true
+    }
+}