feat(10-05): implement CodebergSource for Gitea REST API

- Add CodebergSource targeting /api/v1/repos/search (Codeberg + any Gitea)
- Public API by default; Authorization: token <t> when Token set
- Unauth rate limit 60/hour, authenticated ~1000/hour
- Emit Findings keyed to repo html_url with SourceType=recon:codeberg
- Keyword index maps BuildQueries output back to ProviderName
- httptest coverage: name/interface, rate limits (both modes),
  sweep decoding, header presence/absence, ctx cancellation

pkg/recon/sources/codeberg.go

@@ -0,0 +1,167 @@
+package sources
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"net/url"
+	"time"
+
+	"golang.org/x/time/rate"
+
+	"github.com/salvacybersec/keyhunter/pkg/providers"
+	"github.com/salvacybersec/keyhunter/pkg/recon"
+)
+
+// DefaultCodebergBaseURL is the public Codeberg instance. Any Gitea-compatible
+// server can be substituted by setting CodebergSource.BaseURL.
+const DefaultCodebergBaseURL = "https://codeberg.org"
+
+// CodebergSource implements recon.ReconSource against a Gitea-compatible REST
+// API (Codeberg runs Gitea). Public repository metadata searches do not
+// require authentication; when a Token is provided it is sent as
+// "Authorization: token <t>" which raises Gitea's per-user rate limit from
+// 60/hour to ~1000/hour.
+//
+// Sweep iterates every keyword from the provider registry, queries
+// /api/v1/repos/search?q=<kw>&limit=50, and emits one recon.Finding per
+// returned repository. The html_url is used as Source; the matching provider
+// name is attached so downstream verification can target the correct API.
+type CodebergSource struct {
+	Token    string
+	BaseURL  string
+	Registry *providers.Registry
+	Limiters *recon.LimiterRegistry
+
+	client *Client
+}
+
+// Compile-time interface assertion.
+var _ recon.ReconSource = (*CodebergSource)(nil)
+
+// Name returns the stable identifier used by the limiter registry and
+// Finding.SourceType.
+func (s *CodebergSource) Name() string { return "codeberg" }
+
+// RateLimit returns rate.Every(60s) unauthenticated (60/hour) or
+// rate.Every(3.6s) authenticated (~1000/hour).
+func (s *CodebergSource) RateLimit() rate.Limit {
+	if s.Token == "" {
+		return rate.Every(60 * time.Second)
+	}
+	return rate.Every(3600 * time.Millisecond)
+}
+
+// Burst returns 1 — Gitea's rate limits are per-hour smoothed, a burst of one
+// keeps us safely within headroom for both auth modes.
+func (s *CodebergSource) Burst() int { return 1 }
+
+// RespectsRobots is false — /api/v1/repos/search is a documented REST API.
+func (s *CodebergSource) RespectsRobots() bool { return false }
+
+// Enabled is always true because the /repos/search endpoint works anonymously.
+// A token, when present, only raises the rate limit.
+func (s *CodebergSource) Enabled(_ recon.Config) bool { return true }
+
+// Sweep queries Gitea /api/v1/repos/search for every keyword in the provider
+// registry, decodes the data array, and emits one Finding per result. The
+// query parameter is ignored — Codeberg is swept by provider keyword, not by
+// arbitrary Config.Query text, matching the sibling GitHub/GitLab sources.
+func (s *CodebergSource) Sweep(ctx context.Context, _ string, out chan<- recon.Finding) error {
+	if err := ctx.Err(); err != nil {
+		return err
+	}
+
+	base := s.BaseURL
+	if base == "" {
+		base = DefaultCodebergBaseURL
+	}
+	if s.client == nil {
+		s.client = NewClient()
+	}
+
+	// Build a keyword → providerName map once so emitted findings are
+	// correctly attributed even though BuildQueries returns bare strings.
+	keywordIndex := make(map[string]string)
+	if s.Registry != nil {
+		for _, p := range s.Registry.List() {
+			for _, k := range p.Keywords {
+				if k == "" {
+					continue
+				}
+				if _, exists := keywordIndex[k]; !exists {
+					keywordIndex[k] = p.Name
+				}
+			}
+		}
+	}
+
+	queries := BuildQueries(s.Registry, s.Name())
+	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/api/v1/repos/search?q=%s&limit=50",
+			base, url.QueryEscape(q))
+
+		req, err := http.NewRequestWithContext(ctx, http.MethodGet, endpoint, nil)
+		if err != nil {
+			return fmt.Errorf("codeberg: build request: %w", err)
+		}
+		req.Header.Set("Accept", "application/json")
+		if s.Token != "" {
+			req.Header.Set("Authorization", "token "+s.Token)
+		}
+
+		resp, err := s.client.Do(ctx, req)
+		if err != nil {
+			return fmt.Errorf("codeberg: search %q: %w", q, err)
+		}
+
+		var decoded struct {
+			OK   bool `json:"ok"`
+			Data []struct {
+				FullName string `json:"full_name"`
+				HTMLURL  string `json:"html_url"`
+			} `json:"data"`
+		}
+		if err := json.NewDecoder(resp.Body).Decode(&decoded); err != nil {
+			_, _ = io.Copy(io.Discard, resp.Body)
+			_ = resp.Body.Close()
+			return fmt.Errorf("codeberg: decode: %w", err)
+		}
+		_ = resp.Body.Close()
+
+		provider := keywordIndex[q]
+		for _, item := range decoded.Data {
+			if item.HTMLURL == "" {
+				continue
+			}
+			select {
+			case out <- recon.Finding{
+				ProviderName: provider,
+				Source:       item.HTMLURL,
+				SourceType:   "recon:codeberg",
+				Confidence:   "low",
+				DetectedAt:   time.Now().UTC(),
+			}:
+			case <-ctx.Done():
+				return ctx.Err()
+			}
+		}
+	}
+
+	return nil
+}