feat: 接入 Agnes Image 2.1 Flash 文生图/图生图 API,新增 multipart 上传端点

- utils/t2i.py 重命名为 utils/mm_api_t2i.py(内容不变)
- 新增 utils/agnes_image.py: Agnes 文生图/图生图/多图合成,含 size+ratio 解析、URL/Data URI下载、指数退避重试
- main.py: 修复 utils.t2i import 路径;新增 POST /agnes/images/generations(JSON 版)和 /agnes/images/generations/upload(multipart 版)
- SKILL.md: 同步新端点、可调用模型、调用示例、multipart form 字段说明
- requirements.txt: 新增 python-multipart(UploadFile 依赖)
- .env.example / .env: 新增 AGNES_API_KEY / AGNES_API_BASE_URL
- .gitignore: 忽略 test/ 目录

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

main.py

@@ -4,8 +4,9 @@
 from dotenv import load_dotenv
 
 load_dotenv()
-
-from fastapi import FastAPI
+import base64
+import re
+from fastapi import FastAPI, File, Form, HTTPException, UploadFile
 from fastapi.staticfiles import StaticFiles
 from pydantic import BaseModel, Field, model_validator
 
@@ -97,6 +98,46 @@ def agnes_generate_images_endpoint(request: AgnesImageGenerationRequest):
     return AgnesImageGenerationResponse(**result)
 
 
+_ALLOWED_IMAGE_TYPES = {"image/png", "image/jpeg", "image/jpg", "image/webp"}
+
+
+@app.post("/agnes/images/generations/upload", response_model=AgnesImageGenerationResponse)
+def agnes_generate_images_upload_endpoint(
+    prompt: str = Form(..., description="图片提示词"),
+    profile_name: str = Form(..., description="调用方标识（必填）"),
+    size: str = Form(default="1K", description="输出尺寸档位: 1K / 2K / 3K / 4K"),
+    ratio: str | None = Form(default=None, description=f"宽高比，支持 {sorted(VALID_RATIOS)}"),
+    images: list[UploadFile] = File(default=[], description="参考图像文件，可传多个"),
+):
+    """multipart/form-data 版图生图：上传本地图片文件直接测试，无需 base64。"""
+    if not prompt.strip():
+        raise HTTPException(status_code=422, detail="prompt 不能为空")
+    if not re.match(r"^[\w-]+$", profile_name):
+        raise HTTPException(status_code=422, detail="profile_name 只能包含字母数字下划线和短横线")
+    if not images or all(not f.filename for f in images):
+        raise HTTPException(status_code=422, detail="必须至少上传一张参考图 images")
+
+    data_uris: list[str] = []
+    for f in images:
+        if f.content_type and f.content_type not in _ALLOWED_IMAGE_TYPES:
+            raise HTTPException(status_code=400, detail=f"不支持的图片类型: {f.content_type}")
+        raw = f.file.read()
+        if not raw:
+            raise HTTPException(status_code=400, detail=f"上传的图片 {f.filename} 为空")
+        mime = f.content_type or "image/png"
+        b64 = base64.b64encode(raw).decode("ascii")
+        data_uris.append(f"data:{mime};base64,{b64}")
+
+    result = agnes_generate_images(
+        prompt=prompt,
+        size=size,
+        ratio=ratio,
+        images=data_uris,
+        profile_name=profile_name,
+    )
+    return AgnesImageGenerationResponse(**result)
+
+
 if __name__ == "__main__":
     import uvicorn