feat(13-01): implement CratesIOSource and RubyGemsSource with httptest tests

- CratesIOSource searches crates.io JSON API with custom User-Agent header
- RubyGemsSource searches rubygems.org search.json API for gem matches
- Both credentialless; CratesIO 1 req/s burst 1, RubyGems 1 req/2s burst 2
- Tests verify User-Agent header, Sweep findings, ctx cancellation, metadata

pkg/recon/sources/cratesio_test.go

@@ -0,0 +1,137 @@
+package sources
+
+import (
+	"context"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+	"time"
+
+	"github.com/salvacybersec/keyhunter/pkg/providers"
+	"github.com/salvacybersec/keyhunter/pkg/recon"
+)
+
+func cratesTestRegistry() *providers.Registry {
+	return providers.NewRegistryFromProviders([]providers.Provider{
+		{Name: "openai", Keywords: []string{"sk-proj-"}},
+	})
+}
+
+const cratesFixtureJSON = `{
+  "crates": [
+    {"id": "openai-rs", "name": "openai-rs", "repository": "https://github.com/example/openai-rs"},
+    {"id": "sk-proj-crate", "name": "sk-proj-crate", "repository": ""}
+  ]
+}`
+
+func newCratesIOTestSource(srvURL string) *CratesIOSource {
+	return &CratesIOSource{
+		BaseURL:  srvURL,
+		Registry: cratesTestRegistry(),
+		Limiters: recon.NewLimiterRegistry(),
+		Client:   NewClient(),
+	}
+}
+
+func TestCratesIO_Sweep_ExtractsFindings(t *testing.T) {
+	var hits int
+	var gotUserAgent string
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.URL.Path != "/api/v1/crates" {
+			t.Errorf("unexpected path: %s", r.URL.Path)
+		}
+		if r.URL.Query().Get("q") == "" {
+			t.Errorf("missing q param")
+		}
+		gotUserAgent = r.Header.Get("User-Agent")
+		hits++
+		w.Header().Set("Content-Type", "application/json")
+		_, _ = w.Write([]byte(cratesFixtureJSON))
+	}))
+	defer srv.Close()
+
+	src := newCratesIOTestSource(srv.URL)
+	out := make(chan recon.Finding, 16)
+	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
+	defer cancel()
+
+	if err := src.Sweep(ctx, "", out); err != nil {
+		t.Fatalf("Sweep err: %v", err)
+	}
+	close(out)
+
+	var findings []recon.Finding
+	for f := range out {
+		findings = append(findings, f)
+	}
+	if len(findings) != 2 {
+		t.Fatalf("expected 2 findings, got %d", len(findings))
+	}
+
+	got := map[string]bool{}
+	for _, f := range findings {
+		got[f.Source] = true
+		if f.SourceType != "recon:crates" {
+			t.Errorf("unexpected SourceType: %s", f.SourceType)
+		}
+		if f.Confidence != "low" {
+			t.Errorf("unexpected Confidence: %s", f.Confidence)
+		}
+	}
+	if !got["https://crates.io/crates/openai-rs"] {
+		t.Error("missing openai-rs finding")
+	}
+	if !got["https://crates.io/crates/sk-proj-crate"] {
+		t.Error("missing sk-proj-crate finding")
+	}
+	if hits == 0 {
+		t.Fatal("server was never hit")
+	}
+
+	// Verify custom User-Agent header.
+	if gotUserAgent != "keyhunter-recon/1.0 (https://github.com/salvacybersec/keyhunter)" {
+		t.Errorf("unexpected User-Agent: %s", gotUserAgent)
+	}
+}
+
+func TestCratesIO_EnabledAlwaysTrue(t *testing.T) {
+	s := &CratesIOSource{}
+	if !s.Enabled(recon.Config{}) {
+		t.Fatal("expected Enabled=true")
+	}
+}
+
+func TestCratesIO_Sweep_CtxCancelled(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		time.Sleep(500 * time.Millisecond)
+		_, _ = w.Write([]byte(cratesFixtureJSON))
+	}))
+	defer srv.Close()
+
+	src := newCratesIOTestSource(srv.URL)
+	ctx, cancel := context.WithCancel(context.Background())
+	cancel()
+
+	out := make(chan recon.Finding, 4)
+	if err := src.Sweep(ctx, "", out); err == nil {
+		t.Fatal("expected ctx error")
+	}
+}
+
+func TestCratesIO_NameAndRate(t *testing.T) {
+	s := &CratesIOSource{}
+	if s.Name() != "crates" {
+		t.Errorf("unexpected name: %s", s.Name())
+	}
+	if s.Burst() != 1 {
+		t.Errorf("burst: %d", s.Burst())
+	}
+	if s.RespectsRobots() {
+		t.Error("expected RespectsRobots=false")
+	}
+	want := float64(1) / 1
+	got := float64(s.RateLimit())
+	if got < want-0.01 || got > want+0.01 {
+		t.Errorf("rate limit=%v want~%v", got, want)
+	}
+}