chore: import Local-Cursor v1.1.8 source snapshot

Includes the current working directory changes. Historical commits and release binaries are excluded to limit Gitea storage.
Source base: d7515973fbfd6dd2001fa156c483455b8081c7cb

internal/backend/agent/prompt/content_parts.go

@@ -0,0 +1,15 @@
+package promptengine
+
+// ContentPart 表示一条消息中的结构化内容块。
+type ContentPart struct {
+	Type  string        `json:"type"`
+	Text  string        `json:"text,omitempty"`
+	Image *ImageContent `json:"image,omitempty"`
+}
+
+// ImageContent 表示消息中携带的一张图片。
+type ImageContent struct {
+	MIMEType string `json:"mime_type,omitempty"`
+	Path     string `json:"path,omitempty"`
+	Data     []byte `json:"data,omitempty"`
+}