feat(link-summ): add SummarizeLink API and server integration; youtube oEmbed returns HTML only to avoid duplicate thumbs

internal/summarizer/openai.go

@@ -161,6 +161,90 @@ func (o *OpenAI) Summarize(ctx context.Context, channel string, msgs []store.Mes
 	return out, nil
 }
 
+func (o *OpenAI) SummarizeLink(ctx context.Context, rawURL string) (string, error) {
+	if o == nil || o.apiKey == "" {
+		return "", nil
+	}
+	cfg := openai.DefaultConfig(o.apiKey)
+	if strings.TrimSpace(o.baseURL) != "" {
+		cfg.BaseURL = o.baseURL
+	}
+	client := openai.NewClientWithConfig(cfg)
+
+	content := ""
+	img := ""
+	if isImageURL(rawURL) {
+		img = rawURL
+	} else if o.followLinks {
+		ctx2, cancel := context.WithTimeout(ctx, o.linkTimeout)
+		defer cancel()
+		req, err := http.NewRequestWithContext(ctx2, http.MethodGet, rawURL, nil)
+		if err == nil {
+			resp, err := http.DefaultClient.Do(req)
+			if err == nil {
+				func() {
+					defer resp.Body.Close()
+					if resp.StatusCode >= 200 && resp.StatusCode < 300 {
+						lr := &io.LimitedReader{R: resp.Body, N: int64(o.linkMaxBytes)}
+						b, _ := io.ReadAll(lr)
+						text := string(b)
+						if base, perr := url.Parse(rawURL); perr == nil {
+							if art, err := readability.FromReader(strings.NewReader(text), base); err == nil {
+								if at := strings.TrimSpace(art.TextContent); at != "" {
+									text = at
+								}
+							}
+						}
+						text = strings.ReplaceAll(text, "\r", "")
+						text = strings.TrimSpace(text)
+						if len(text) > 6000 { text = text[:6000] }
+						content = text
+					}
+				}()
+			}
+		}
+	}
+
+	// Build link-specific prompt
+	sys := "You summarize the content at a single URL. Ignore surrounding chat context. Be concise and natural."
+	var userParts []openai.ChatMessagePart
+	b := strings.Builder{}
+	b.WriteString("URL: ")
+	b.WriteString(rawURL)
+	b.WriteString("\n\n")
+	if content != "" {
+		b.WriteString("Extracted content (may be truncated):\n")
+		b.WriteString(content)
+		b.WriteString("\n\n")
+	}
+	b.WriteString("Write a short, skimmable summary of the page/video/image above. If relevant, include key takeaways and any notable cautions. Keep it under a few short paragraphs.")
+	userParts = append(userParts, openai.ChatMessagePart{Type: openai.ChatMessagePartTypeText, Text: b.String()})
+	if img != "" {
+		userParts = append(userParts, openai.ChatMessagePart{Type: openai.ChatMessagePartTypeImageURL, ImageURL: &openai.ChatMessageImageURL{URL: img}})
+	}
+
+	model := o.model
+	if strings.TrimSpace(model) == "" {
+		model = "gpt-4o-mini"
+	}
+	reasoningLike := strings.HasPrefix(model, "gpt-5") || strings.HasPrefix(model, "o1") || strings.Contains(model, "reasoning")
+
+	req := openai.ChatCompletionRequest{
+		Model: model,
+		Messages: []openai.ChatCompletionMessage{
+			{Role: openai.ChatMessageRoleSystem, Content: sys},
+			{Role: openai.ChatMessageRoleUser, MultiContent: userParts},
+		},
+		MaxCompletionTokens: o.maxTokens,
+	}
+	if !reasoningLike { req.Temperature = 0.2 }
+
+	resp, err := client.CreateChatCompletion(ctx, req)
+	if err != nil { return "", err }
+	if len(resp.Choices) == 0 { return "", nil }
+	return strings.TrimSpace(resp.Choices[0].Message.Content), nil
+}
+
 func linksFromImages(imgs []string) []linkSnippet {
 	out := make([]linkSnippet, 0, len(imgs))
 	for _, u := range imgs {

internal/summarizer/summarizer.go

@@ -9,6 +9,7 @@ import (
 
 type Summarizer interface {
     Summarize(ctx context.Context, channel string, msgs []store.Message, window time.Duration) (string, error)
+    SummarizeLink(ctx context.Context, rawURL string) (string, error)
 }