feat(14-03): implement SourceMapSource, WebpackSource, EnvLeakSource with tests

- SourceMapSource probes .map files for original source containing API keys
- WebpackSource scans JS bundles for inlined NEXT_PUBLIC_/REACT_APP_/VITE_ env vars
- EnvLeakSource probes common .env paths for exposed environment files
- All three implement ReconSource, credentialless, with httptest-based tests

pkg/recon/sources/sourcemap.go

@@ -0,0 +1,123 @@
+package sources
+
+import (
+	"context"
+	"encoding/json"
+	"net/http"
+	"regexp"
+	"time"
+
+	"golang.org/x/time/rate"
+
+	"github.com/salvacybersec/keyhunter/pkg/providers"
+	"github.com/salvacybersec/keyhunter/pkg/recon"
+)
+
+// SourceMapSource probes for publicly accessible JavaScript source maps (.map
+// files) that contain original source code. Developers frequently ship source
+// maps to production, exposing server-side secrets embedded during bundling.
+type SourceMapSource struct {
+	BaseURL  string
+	Registry *providers.Registry
+	Limiters *recon.LimiterRegistry
+	Client   *Client
+}
+
+var _ recon.ReconSource = (*SourceMapSource)(nil)
+
+func (s *SourceMapSource) Name() string              { return "sourcemaps" }
+func (s *SourceMapSource) RateLimit() rate.Limit      { return rate.Every(3 * time.Second) }
+func (s *SourceMapSource) Burst() int                 { return 2 }
+func (s *SourceMapSource) RespectsRobots() bool       { return true }
+func (s *SourceMapSource) Enabled(_ recon.Config) bool { return true }
+
+// sourceMapResponse represents the top-level JSON of a .map file.
+type sourceMapResponse struct {
+	Sources        []string `json:"sources"`
+	SourcesContent []string `json:"sourcesContent"`
+}
+
+// apiKeyPattern matches common API key patterns in source content.
+var apiKeyPattern = regexp.MustCompile(`(?i)(api[_-]?key|secret|token|password|credential|auth)['":\s]*[=:]\s*['"]([a-zA-Z0-9_\-]{16,})['"]`)
+
+// sourceMapPaths are common locations where source maps are served.
+var sourceMapPaths = []string{
+	"/static/js/main.js.map",
+	"/static/js/bundle.js.map",
+	"/assets/index.js.map",
+	"/dist/bundle.js.map",
+	"/main.js.map",
+	"/app.js.map",
+	"/_next/static/chunks/main.js.map",
+}
+
+func (s *SourceMapSource) Sweep(ctx context.Context, _ string, out chan<- recon.Finding) error {
+	base := s.BaseURL
+	client := s.Client
+	if client == nil {
+		client = NewClient()
+	}
+
+	queries := BuildQueries(s.Registry, "sourcemaps")
+	if len(queries) == 0 {
+		return nil
+	}
+
+	for _, q := range queries {
+		if err := ctx.Err(); err != nil {
+			return err
+		}
+
+		// Each query is used as a domain/URL hint; probe common map paths.
+		for _, path := range sourceMapPaths {
+			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
+				}
+			}
+
+			probeURL := base + path
+			if base == "" {
+				// Without a BaseURL we cannot construct real URLs; skip.
+				continue
+			}
+
+			req, err := http.NewRequestWithContext(ctx, http.MethodGet, probeURL, nil)
+			if err != nil {
+				continue
+			}
+			req.Header.Set("Accept", "application/json")
+
+			resp, err := client.Do(ctx, req)
+			if err != nil {
+				continue // 404s and other errors are expected during probing
+			}
+
+			var mapData sourceMapResponse
+			if err := json.NewDecoder(resp.Body).Decode(&mapData); err != nil {
+				_ = resp.Body.Close()
+				continue
+			}
+			_ = resp.Body.Close()
+
+			// Scan sourcesContent for API key patterns.
+			for _, content := range mapData.SourcesContent {
+				if apiKeyPattern.MatchString(content) {
+					out <- recon.Finding{
+						ProviderName: q,
+						Source:       probeURL,
+						SourceType:   "recon:sourcemaps",
+						Confidence:   "medium",
+						DetectedAt:   time.Now(),
+					}
+					break // one finding per map file is sufficient
+				}
+			}
+		}
+	}
+	return nil
+}