feat(11-01): add GoogleDorkSource and BingDorkSource with formatQuery updates

- GoogleDorkSource uses Google Custom Search JSON API (APIKey+CX required)
- BingDorkSource uses Bing Web Search API v7 (Ocp-Apim-Subscription-Key header)
- formatQuery now handles google/bing/duckduckgo/yandex/brave dork syntax
- Both sources follow established pattern: retry via Client, rate limit via LimiterRegistry

pkg/recon/sources/google.go

@@ -0,0 +1,172 @@
+package sources
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"net/http"
+	"net/url"
+	"strings"
+	"time"
+
+	"golang.org/x/time/rate"
+
+	"github.com/salvacybersec/keyhunter/pkg/providers"
+	"github.com/salvacybersec/keyhunter/pkg/recon"
+)
+
+// GoogleDorkSource implements recon.ReconSource against the Google Custom
+// Search JSON API. It iterates provider keyword queries (via BuildQueries)
+// and emits a recon.Finding for every search result item returned.
+//
+// Both APIKey and CX (custom search engine ID) must be set for the source to
+// be enabled. Missing credentials disable the source without error.
+type GoogleDorkSource struct {
+	APIKey   string
+	CX       string
+	BaseURL  string
+	Registry *providers.Registry
+	Limiters *recon.LimiterRegistry
+	client   *Client
+}
+
+// Compile-time assertion.
+var _ recon.ReconSource = (*GoogleDorkSource)(nil)
+
+// NewGoogleDorkSource constructs a GoogleDorkSource with the shared retry client.
+func NewGoogleDorkSource(apiKey, cx string, reg *providers.Registry, lim *recon.LimiterRegistry) *GoogleDorkSource {
+	return &GoogleDorkSource{
+		APIKey:   apiKey,
+		CX:       cx,
+		BaseURL:  "https://www.googleapis.com",
+		Registry: reg,
+		Limiters: lim,
+		client:   NewClient(),
+	}
+}
+
+func (s *GoogleDorkSource) Name() string          { return "google" }
+func (s *GoogleDorkSource) RateLimit() rate.Limit { return rate.Every(1 * time.Second) }
+func (s *GoogleDorkSource) Burst() int            { return 1 }
+func (s *GoogleDorkSource) RespectsRobots() bool  { return false }
+
+// Enabled returns true only when both APIKey and CX are configured.
+func (s *GoogleDorkSource) Enabled(_ recon.Config) bool {
+	return s.APIKey != "" && s.CX != ""
+}
+
+// Sweep issues one Custom Search request per provider keyword and emits a
+// Finding for every result item.
+func (s *GoogleDorkSource) Sweep(ctx context.Context, _ string, out chan<- recon.Finding) error {
+	if s.APIKey == "" || s.CX == "" {
+		return nil
+	}
+	base := s.BaseURL
+	if base == "" {
+		base = "https://www.googleapis.com"
+	}
+
+	queries := BuildQueries(s.Registry, "google")
+	kwIndex := googleKeywordIndex(s.Registry)
+
+	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
+			}
+		}
+
+		endpoint := fmt.Sprintf("%s/customsearch/v1?key=%s&cx=%s&q=%s&num=10",
+			base, url.QueryEscape(s.APIKey), url.QueryEscape(s.CX), url.QueryEscape(q))
+		req, err := http.NewRequestWithContext(ctx, http.MethodGet, endpoint, nil)
+		if err != nil {
+			return fmt.Errorf("google: build request: %w", err)
+		}
+		req.Header.Set("Accept", "application/json")
+		req.Header.Set("User-Agent", "keyhunter-recon")
+
+		resp, err := s.client.Do(ctx, req)
+		if err != nil {
+			if errors.Is(err, ErrUnauthorized) {
+				return err
+			}
+			if errors.Is(err, context.Canceled) || errors.Is(err, context.DeadlineExceeded) {
+				return err
+			}
+			continue
+		}
+
+		var parsed googleSearchResponse
+		decErr := json.NewDecoder(resp.Body).Decode(&parsed)
+		_ = resp.Body.Close()
+		if decErr != nil {
+			continue
+		}
+
+		provName := kwIndex[strings.ToLower(extractGoogleKeyword(q))]
+		for _, it := range parsed.Items {
+			f := recon.Finding{
+				ProviderName: provName,
+				Confidence:   "low",
+				Source:       it.Link,
+				SourceType:   "recon:google",
+				DetectedAt:   time.Now(),
+			}
+			select {
+			case out <- f:
+			case <-ctx.Done():
+				return ctx.Err()
+			}
+		}
+	}
+	return nil
+}
+
+type googleSearchResponse struct {
+	Items []googleSearchItem `json:"items"`
+}
+
+type googleSearchItem struct {
+	Title   string `json:"title"`
+	Link    string `json:"link"`
+	Snippet string `json:"snippet"`
+}
+
+// googleKeywordIndex maps lowercased keywords to provider names.
+func googleKeywordIndex(reg *providers.Registry) map[string]string {
+	m := make(map[string]string)
+	if reg == nil {
+		return m
+	}
+	for _, p := range reg.List() {
+		for _, k := range p.Keywords {
+			kl := strings.ToLower(strings.TrimSpace(k))
+			if kl == "" {
+				continue
+			}
+			if _, exists := m[kl]; !exists {
+				m[kl] = p.Name
+			}
+		}
+	}
+	return m
+}
+
+// extractGoogleKeyword reverses the dork query format to recover the keyword.
+func extractGoogleKeyword(q string) string {
+	// Format: site:pastebin.com OR site:github.com "keyword"
+	idx := strings.LastIndex(q, `"`)
+	if idx <= 0 {
+		return q
+	}
+	inner := q[:idx]
+	start := strings.LastIndex(inner, `"`)
+	if start < 0 {
+		return q
+	}
+	return inner[start+1:]
+}