feat(13-03): implement TerraformSource and HelmSource

- Terraform searches registry.terraform.io v1 modules API with namespace/name/provider URLs
- Helm searches artifacthub.io for charts (kind=0) with repo/chart URL construction
- Both sources: context cancellation, nil registry, httptest-based tests

pkg/recon/sources/terraform.go

@@ -0,0 +1,131 @@
+package sources
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"net/url"
+	"time"
+
+	"golang.org/x/time/rate"
+
+	"github.com/salvacybersec/keyhunter/pkg/providers"
+	"github.com/salvacybersec/keyhunter/pkg/recon"
+)
+
+// TerraformSource searches the Terraform Registry for modules matching
+// provider keywords. Modules that reference LLM/AI provider credentials may
+// contain hardcoded API keys in their variable defaults or examples.
+//
+// Emits one Finding per module result, tagged SourceType=recon:terraform.
+type TerraformSource struct {
+	// BaseURL defaults to https://registry.terraform.io. Tests override.
+	BaseURL string
+	// Registry drives the keyword query list via BuildQueries.
+	Registry *providers.Registry
+	// Limiters is the shared recon.LimiterRegistry.
+	Limiters *recon.LimiterRegistry
+	// Client is the shared retry HTTP wrapper. If nil, a default is used.
+	Client *Client
+}
+
+// Compile-time assertion that TerraformSource satisfies recon.ReconSource.
+var _ recon.ReconSource = (*TerraformSource)(nil)
+
+func (s *TerraformSource) Name() string          { return "terraform" }
+func (s *TerraformSource) RateLimit() rate.Limit { return rate.Every(2 * time.Second) }
+func (s *TerraformSource) Burst() int            { return 2 }
+func (s *TerraformSource) RespectsRobots() bool  { return false }
+
+// Enabled always returns true: Terraform Registry search is unauthenticated.
+func (s *TerraformSource) Enabled(_ recon.Config) bool { return true }
+
+// Sweep iterates provider keywords, searches Terraform Registry for matching
+// modules, and emits a Finding for each result.
+func (s *TerraformSource) Sweep(ctx context.Context, _ string, out chan<- recon.Finding) error {
+	base := s.BaseURL
+	if base == "" {
+		base = "https://registry.terraform.io"
+	}
+	client := s.Client
+	if client == nil {
+		client = NewClient()
+	}
+
+	queries := BuildQueries(s.Registry, "terraform")
+	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
+			}
+		}
+
+		endpoint := fmt.Sprintf("%s/v1/modules?q=%s&limit=20",
+			base, url.QueryEscape(q))
+		req, err := http.NewRequestWithContext(ctx, http.MethodGet, endpoint, nil)
+		if err != nil {
+			return fmt.Errorf("terraform: build req: %w", err)
+		}
+		req.Header.Set("Accept", "application/json")
+
+		resp, err := client.Do(ctx, req)
+		if err != nil {
+			continue
+		}
+
+		var parsed terraformSearchResponse
+		decErr := json.NewDecoder(resp.Body).Decode(&parsed)
+		_ = resp.Body.Close()
+		if decErr != nil {
+			continue
+		}
+
+		for _, mod := range parsed.Modules {
+			if err := ctx.Err(); err != nil {
+				return err
+			}
+
+			sourceURL := fmt.Sprintf("https://registry.terraform.io/modules/%s/%s/%s",
+				mod.Namespace, mod.Name, mod.Provider)
+			if base != "https://registry.terraform.io" {
+				sourceURL = fmt.Sprintf("%s/modules/%s/%s/%s",
+					base, mod.Namespace, mod.Name, mod.Provider)
+			}
+
+			f := recon.Finding{
+				ProviderName: "",
+				Source:       sourceURL,
+				SourceType:   "recon:terraform",
+				Confidence:   "low",
+				DetectedAt:   time.Now(),
+			}
+			select {
+			case out <- f:
+			case <-ctx.Done():
+				return ctx.Err()
+			}
+		}
+	}
+	return nil
+}
+
+type terraformSearchResponse struct {
+	Modules []terraformModule `json:"modules"`
+}
+
+type terraformModule struct {
+	ID          string `json:"id"`
+	Namespace   string `json:"namespace"`
+	Name        string `json:"name"`
+	Provider    string `json:"provider"`
+	Description string `json:"description"`
+}