feat(15-01): add Discord, Slack, DevTo recon sources and wire all six

- DiscordSource uses dorking approach against configurable search endpoint
- SlackSource uses dorking against slack-archive indexers
- DevToSource searches dev.to API articles list + detail for body_markdown
- RegisterAll extended to include all 6 Phase 15 forum sources
- All credentialless, use ciLogKeyPattern for key detection

pkg/recon/sources/devto.go

@@ -0,0 +1,156 @@
+package sources
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"net/url"
+	"time"
+
+	"golang.org/x/time/rate"
+
+	"github.com/salvacybersec/keyhunter/pkg/providers"
+	"github.com/salvacybersec/keyhunter/pkg/recon"
+)
+
+// DevToSource searches the dev.to public API for articles containing leaked
+// API keys. Developers write tutorials and guides on dev.to that sometimes
+// include real credentials in code examples.
+type DevToSource struct {
+	BaseURL  string
+	Registry *providers.Registry
+	Limiters *recon.LimiterRegistry
+	Client   *Client
+}
+
+var _ recon.ReconSource = (*DevToSource)(nil)
+
+func (s *DevToSource) Name() string               { return "devto" }
+func (s *DevToSource) RateLimit() rate.Limit       { return rate.Every(1 * time.Second) }
+func (s *DevToSource) Burst() int                  { return 5 }
+func (s *DevToSource) RespectsRobots() bool        { return false }
+func (s *DevToSource) Enabled(_ recon.Config) bool { return true }
+
+// devtoArticleSummary represents an article in the dev.to /api/articles list response.
+type devtoArticleSummary struct {
+	ID  int    `json:"id"`
+	URL string `json:"url"`
+}
+
+// devtoArticleDetail represents the full article from /api/articles/{id}.
+type devtoArticleDetail struct {
+	BodyMarkdown string `json:"body_markdown"`
+	URL          string `json:"url"`
+}
+
+func (s *DevToSource) Sweep(ctx context.Context, _ string, out chan<- recon.Finding) error {
+	base := s.BaseURL
+	if base == "" {
+		base = "https://dev.to"
+	}
+	client := s.Client
+	if client == nil {
+		client = NewClient()
+	}
+
+	queries := BuildQueries(s.Registry, "devto")
+	if len(queries) == 0 {
+		return nil
+	}
+
+	for _, q := range queries {
+		if err := ctx.Err(); err != nil {
+			return err
+		}
+
+		if s.Limiters != nil {
+			if err := s.Limiters.Wait(ctx, s.Name(), s.RateLimit(), s.Burst(), false); err != nil {
+				return err
+			}
+		}
+
+		// Search for articles by tag keyword.
+		listURL := fmt.Sprintf("%s/api/articles?tag=%s&per_page=10&state=rising",
+			base, url.QueryEscape(q))
+		req, err := http.NewRequestWithContext(ctx, http.MethodGet, listURL, nil)
+		if err != nil {
+			continue
+		}
+		req.Header.Set("Accept", "application/json")
+
+		resp, err := client.Do(ctx, req)
+		if err != nil {
+			continue
+		}
+
+		body, err := io.ReadAll(io.LimitReader(resp.Body, 256*1024))
+		_ = resp.Body.Close()
+		if err != nil {
+			continue
+		}
+
+		var articles []devtoArticleSummary
+		if err := json.Unmarshal(body, &articles); err != nil {
+			continue
+		}
+
+		// Limit to first 5 articles to stay within rate limits.
+		limit := 5
+		if len(articles) < limit {
+			limit = len(articles)
+		}
+
+		for _, article := range articles[:limit] {
+			if err := ctx.Err(); err != nil {
+				return err
+			}
+
+			if s.Limiters != nil {
+				if err := s.Limiters.Wait(ctx, s.Name(), s.RateLimit(), s.Burst(), false); err != nil {
+					return err
+				}
+			}
+
+			// Fetch full article to get body_markdown.
+			detailURL := fmt.Sprintf("%s/api/articles/%d", base, article.ID)
+			detailReq, err := http.NewRequestWithContext(ctx, http.MethodGet, detailURL, nil)
+			if err != nil {
+				continue
+			}
+			detailReq.Header.Set("Accept", "application/json")
+
+			detailResp, err := client.Do(ctx, detailReq)
+			if err != nil {
+				continue
+			}
+
+			detailBody, err := io.ReadAll(io.LimitReader(detailResp.Body, 256*1024))
+			_ = detailResp.Body.Close()
+			if err != nil {
+				continue
+			}
+
+			var detail devtoArticleDetail
+			if err := json.Unmarshal(detailBody, &detail); err != nil {
+				continue
+			}
+
+			if ciLogKeyPattern.MatchString(detail.BodyMarkdown) {
+				articleURL := detail.URL
+				if articleURL == "" {
+					articleURL = fmt.Sprintf("%s/api/articles/%d", base, article.ID)
+				}
+				out <- recon.Finding{
+					ProviderName: q,
+					Source:       articleURL,
+					SourceType:   "recon:devto",
+					Confidence:   "medium",
+					DetectedAt:   time.Now(),
+				}
+			}
+		}
+	}
+	return nil
+}