feat(10-01): add provider-driven query generator and RegisterAll skeleton

- BuildQueries(reg, source) dedups keywords and formats per-source syntax
- github/gist use 'keyword' in:file; others use bare keyword
- SourcesConfig placeholder struct for Wave 2 plans to depend on
- RegisterAll no-op stub (Plan 10-09 will fill)

pkg/recon/sources/register.go

@@ -0,0 +1,32 @@
+package sources
+
+import (
+	"github.com/salvacybersec/keyhunter/pkg/providers"
+	"github.com/salvacybersec/keyhunter/pkg/recon"
+)
+
+// SourcesConfig carries per-source credentials and shared dependencies read
+// from viper/env by cmd/recon.go. Plan 10-09 fleshes this out; for now it is a
+// placeholder struct so Wave 2 plans can depend on its shape.
+type SourcesConfig struct {
+	GitHubToken      string
+	GitLabToken      string
+	BitbucketToken   string
+	HuggingFaceToken string
+	KaggleUser       string
+	KaggleKey        string
+
+	Registry *providers.Registry
+	Limiters *recon.LimiterRegistry
+}
+
+// RegisterAll registers every Phase 10 code-hosting source on engine.
+// Wave 2 plans append their source constructors here via additional
+// registerXxx helpers in this file. Plan 10-09 writes the final list.
+func RegisterAll(engine *recon.Engine, cfg SourcesConfig) {
+	if engine == nil {
+		return
+	}
+	_ = cfg // wired up in Wave 2 + Plan 10-09
+	// Populated by Plan 10-09 (after Wave 2 lands individual source files).
+}