fix(Discord&Generator): 修复 Discord 图片发送失败及渲染错误处理

- DiscordAdapter: 增加对 base64:// 协议的支持
- ReportGenerator: 增加图片文件头校验，防止将渲染器的错误文本(Internal Server Error)当作图片发送

src/infrastructure/platform/adapters/discord_adapter.py

@@ -397,7 +397,20 @@ class DiscordAdapter(PlatformAdapter):
                 return False
 
             file_to_send = None
-            if image_path.startswith(("http://", "https://")):
+            if image_path.startswith("base64://"):
+                # Base64 图片：解码 -> 内存 Object -> Discord
+                from io import BytesIO
+                try:
+                    base64_data = image_path.split("base64://")[1]
+                    image_bytes = base64.b64decode(base64_data)
+                    file_to_send = discord.File(
+                        BytesIO(image_bytes), filename="daily_report_image.png"
+                    )
+                except Exception as e:
+                    logger.error(f"Discord Base64 图片解码失败: {e}")
+                    return False
+
+            elif image_path.startswith(("http://", "https://")):
                 # 远程图片：下载 -> 内存 Object -> Discord
                 from io import BytesIO
 

src/infrastructure/reporting/generators.py

@@ -132,6 +132,25 @@ class ReportGenerator(IReportGenerator):
                                     if os.path.exists(image_data):
                                         with open(image_data, "rb") as f:
                                             file_bytes = f.read()
+                                        
+                                        # 校验是否为有效图片 (防止发送 "Internal Server Error" 文本)
+                                        is_valid_image = False
+                                        if file_bytes.startswith(b"\xff\xd8"): # JPEG
+                                            is_valid_image = True
+                                        elif file_bytes.startswith(b"\x89PNG\r\n\x1a\n"): # PNG
+                                            is_valid_image = True
+                                        
+                                        if not is_valid_image:
+                                            try:
+                                                text_content = file_bytes.decode('utf-8')
+                                                if "Error" in text_content or "Exception" in text_content:
+                                                    logger.error(f"渲染器生成了错误文件而非图片: {text_content[:200]}")
+                                                    return None, html_content
+                                            except Exception:
+                                                pass
+                                            logger.warning(f"生成的图片文件头异常 (非JPEG/PNG): {file_bytes[:10].hex()}")
+                                            return None, html_content
+
                                         b64 = base64.b64encode(file_bytes).decode("utf-8")
                                         image_url = f"base64://{b64}"
                                         logger.info(f"本地图片转 Base64 成功: {len(file_bytes)} bytes")