feat(16-02): add APKMirror and crt.sh ReconSource modules

- APKMirrorSource searches APK metadata pages for key patterns
- CrtShSource discovers subdomains via CT logs and probes config endpoints
- Both credentialless, emit findings on ciLogKeyPattern match

pkg/recon/sources/apkmirror.go

@@ -0,0 +1,94 @@
+package sources
+
+import (
+	"context"
+	"fmt"
+	"io"
+	"net/http"
+	"net/url"
+	"time"
+
+	"golang.org/x/time/rate"
+
+	"github.com/salvacybersec/keyhunter/pkg/providers"
+	"github.com/salvacybersec/keyhunter/pkg/recon"
+)
+
+// APKMirrorSource searches APKMirror for mobile app metadata (descriptions,
+// changelogs, file listings) that may contain leaked API keys. This is a
+// metadata scanner -- it does not decompile APKs. Full decompilation via
+// apktool/jadx would require local binary dependencies and is out of scope
+// for a network-based ReconSource.
+type APKMirrorSource struct {
+	BaseURL  string
+	Registry *providers.Registry
+	Limiters *recon.LimiterRegistry
+	Client   *Client
+}
+
+var _ recon.ReconSource = (*APKMirrorSource)(nil)
+
+func (s *APKMirrorSource) Name() string               { return "apkmirror" }
+func (s *APKMirrorSource) RateLimit() rate.Limit       { return rate.Every(5 * time.Second) }
+func (s *APKMirrorSource) Burst() int                  { return 2 }
+func (s *APKMirrorSource) RespectsRobots() bool        { return true }
+func (s *APKMirrorSource) Enabled(_ recon.Config) bool { return true }
+
+func (s *APKMirrorSource) Sweep(ctx context.Context, query string, out chan<- recon.Finding) error {
+	base := s.BaseURL
+	if base == "" {
+		base = "https://www.apkmirror.com"
+	}
+	client := s.Client
+	if client == nil {
+		client = NewClient()
+	}
+
+	queries := BuildQueries(s.Registry, "apkmirror")
+	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
+			}
+		}
+
+		searchURL := fmt.Sprintf(
+			"%s/?post_type=app_release&searchtype=apk&s=%s",
+			base, url.QueryEscape(q),
+		)
+		req, err := http.NewRequestWithContext(ctx, http.MethodGet, searchURL, nil)
+		if err != nil {
+			continue
+		}
+
+		resp, err := client.Do(ctx, req)
+		if err != nil {
+			continue
+		}
+
+		body, err := io.ReadAll(io.LimitReader(resp.Body, 512*1024))
+		_ = resp.Body.Close()
+		if err != nil {
+			continue
+		}
+
+		if ciLogKeyPattern.Match(body) {
+			out <- recon.Finding{
+				ProviderName: q,
+				Source:       searchURL,
+				SourceType:   "recon:apkmirror",
+				Confidence:   "medium",
+				DetectedAt:   time.Now(),
+			}
+		}
+	}
+	return nil
+}