refactor: output channel interface (payload/meta/type) + memory fixes

- Redesign output_send__ tools: content JSON string -> structured
  payload/meta/type params for LLM reliability
- executeOutputSendTool: route by type with capability check
- executeOutputSendHelp: show meta format + type enum
- Updated system prompt rules for new interface
- docToTriples: use jieba exact mode adjacent co-occurrence
- Unify vector space: Doc.Vector field, ContextToDoc vectorizer,
  ReindexWithVectorizer on startup

internal/memory/cut.go

@@ -117,3 +117,26 @@ func ExtractKeywords(text string) []string {
 	}
 	return keywords
 }
+
+// CutExact 精确模式分词：返回去停用词后的所有有义项（不限数量），用于 doc→graph 蒸馏
+func CutExact(text string) []string {
+	text = CleanTemplateText(text)
+	x := GetJieba()
+	if x == nil {
+		return nil
+	}
+	words := x.Cut(text, false)
+	var result []string
+	seen := make(map[string]bool)
+	for _, w := range words {
+		if stopWords[w] || seen[w] {
+			continue
+		}
+		if !validEntityName(w) {
+			continue
+		}
+		seen[w] = true
+		result = append(result, w)
+	}
+	return result
+}