POD 趋势感知 Agent：缓存热点模式 + 三图合成 + 热点去重/风格去重 + review 兜底

- 缓存热点批量流程（有采集缓存不触发 Google）
- 简报不足直接从采集缓存生成（轻量补齐）
- 三图合成（模特/印花/底图）+ 底图压缩 <2MB
- 热点去重→风格去重自动切换 + 不适合类目 review 兜底
- 透明背景（background=transparent）+ 提示词清洗（敏感词/背景描述）
- 任务前 basemap 校验 + 模板国家校验 + 模特任务级分配

graph/backends/mock_image_backend.py

@@ -0,0 +1,65 @@
+"""Mock 图像后端：Pillow 生成占位图。
+
+无 OpenAI key 时也能端到端演示产品流水线（选品 → 底图 → "印花图" → "模特合成" 产物齐全）。
+占位图 = 参考图尺寸 + 文字标注（提示词摘要），明确标识 [MOCK] 避免误用。
+"""
+from pathlib import Path
+
+from PIL import Image, ImageDraw
+
+from .base import ImageBackend
+
+
+class MockImageBackend(ImageBackend):
+    name = "mock"
+
+    def __init__(self):
+        self._cfg: dict = {}
+
+    def bind_config(self, cfg: dict):
+        self._cfg = cfg or {}
+
+    def print(self, prompt: str, base_image: str, out_path: str, negative: str = "",
+              extra_images=None, size: str = "") -> str:
+        size_px = (1024, 1024)
+        try:
+            with Image.open(base_image) as im:
+                size_px = im.size
+        except Exception:
+            pass
+        if size:
+            try:
+                w, h = (int(x) for x in str(size).lower().split("x"))
+                size_px = (w, h)
+            except Exception:
+                pass
+        img = Image.new("RGB", size_px, (240, 240, 248))
+        d = ImageDraw.Draw(img)
+        d.rectangle([0, 0, size_px[0] - 1, size_px[1] - 1], outline=(180, 180, 200))
+        d.text((24, 24), f"[MOCK] {Path(out_path).name}", fill=(50, 50, 80))
+        d.text((24, 56), "（未配置 OpenAI key，占位图演示流程）", fill=(120, 120, 150))
+        d.text((24, 96), (prompt or "")[:160], fill=(90, 90, 120))
+        if extra_images:
+            d.text((24, 136), f"参考图 {len(list(extra_images))} 张: " + ", ".join(Path(p).name[:24] for p in extra_images), fill=(90, 90, 120))
+        Path(out_path).parent.mkdir(parents=True, exist_ok=True)
+        img.save(out_path)
+        return out_path
+
+    def generate(self, prompt: str, out_path: str, negative: str = "", size: str = "") -> str:
+        """纯文生图（mock）：白底 + 文字标注，模拟纯印花设计稿。"""
+        size_px = (1024, 1024)
+        if size:
+            try:
+                w, h = (int(x) for x in str(size).lower().split("x"))
+                size_px = (w, h)
+            except Exception:
+                pass
+        img = Image.new("RGB", size_px, (252, 252, 252))
+        d = ImageDraw.Draw(img)
+        d.rectangle([0, 0, size_px[0] - 1, size_px[1] - 1], outline=(200, 200, 210))
+        d.text((24, 24), f"[MOCK DESIGN] {Path(out_path).name}", fill=(50, 50, 80))
+        d.text((24, 56), "（纯印花设计稿占位，白底）", fill=(120, 120, 150))
+        d.text((24, 96), (prompt or "")[:160], fill=(90, 90, 120))
+        Path(out_path).parent.mkdir(parents=True, exist_ok=True)
+        img.save(out_path)
+        return out_path